WO2022124000A1 - Laminate and laminated structure - Google Patents

Laminate and laminated structure Download PDF

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Publication number
WO2022124000A1
WO2022124000A1 PCT/JP2021/041559 JP2021041559W WO2022124000A1 WO 2022124000 A1 WO2022124000 A1 WO 2022124000A1 JP 2021041559 W JP2021041559 W JP 2021041559W WO 2022124000 A1 WO2022124000 A1 WO 2022124000A1
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WO
WIPO (PCT)
Prior art keywords
sensitive adhesive
meth
adhesive sheet
photopolymerization initiator
pressure
Prior art date
Application number
PCT/JP2021/041559
Other languages
French (fr)
Japanese (ja)
Inventor
大希 野澤
Original Assignee
三菱ケミカル株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 三菱ケミカル株式会社 filed Critical 三菱ケミカル株式会社
Priority to JP2022568128A priority Critical patent/JPWO2022124000A1/ja
Priority to KR1020237015903A priority patent/KR20230114744A/en
Priority to CN202180075859.7A priority patent/CN116438271A/en
Publication of WO2022124000A1 publication Critical patent/WO2022124000A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C08K5/0025—Crosslinking or vulcanising agents; including accelerators
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J11/00—Features of adhesives not provided for in group C09J9/00, e.g. additives
    • C09J11/02—Non-macromolecular additives
    • C09J11/06—Non-macromolecular additives organic
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J133/00—Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by only one carboxyl radical, or of salts, anhydrides, esters, amides, imides, or nitriles thereof; Adhesives based on derivatives of such polymers
    • C09J133/04—Homopolymers or copolymers of esters
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J151/00—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers
    • C09J151/06—Adhesives based on graft polymers in which the grafted component is obtained by reactions only involving carbon-to-carbon unsaturated bonds; Adhesives based on derivatives of such polymers grafted on to homopolymers or copolymers of aliphatic hydrocarbons containing only one carbon-to-carbon double bond
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J7/00—Adhesives in the form of films or foils
    • C09J7/30—Adhesives in the form of films or foils characterised by the adhesive composition
    • C09J7/38—Pressure-sensitive adhesives [PSA]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2203/00—Applications of adhesives in processes or use of adhesives in the form of films or foils
    • C09J2203/318—Applications of adhesives in processes or use of adhesives in the form of films or foils for the production of liquid crystal displays
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/30—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier
    • C09J2301/312—Additional features of adhesives in the form of films or foils characterized by the chemical, physicochemical or physical properties of the adhesive or the carrier parameters being the characterizing feature
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09J—ADHESIVES; NON-MECHANICAL ASPECTS OF ADHESIVE PROCESSES IN GENERAL; ADHESIVE PROCESSES NOT PROVIDED FOR ELSEWHERE; USE OF MATERIALS AS ADHESIVES
    • C09J2301/00—Additional features of adhesives in the form of films or foils
    • C09J2301/40—Additional features of adhesives in the form of films or foils characterized by the presence of essential components
    • C09J2301/416—Additional features of adhesives in the form of films or foils characterized by the presence of essential components use of irradiation

Definitions

  • the present invention is a laminate provided with an adhesive sheet used for bonding a resin member having an ultraviolet ray blocking property that does not transmit ultraviolet rays, and has a performance of being cured by irradiating with light (hereinafter referred to as "photocuring property"). It relates to a laminate having a photocurable pressure-sensitive adhesive sheet (referred to as).
  • an image display panel such as a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), and protection placed on the front side (visual side) thereof.
  • LCD liquid crystal display
  • PDP plasma display
  • ELD electroluminescence display
  • protection placed on the front side (visual side) thereof.
  • window members and fronts are used to prevent yellowing deterioration of resin members such as conductive members and polarizing plates inside the image display devices due to ultraviolet exposure.
  • a constituent member such as a glass cover member or a resin cover member having an ultraviolet shielding property may be used.
  • a photocurable adhesive sheet that can be photocured by light in a wavelength range that can pass through the ultraviolet shielding component when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component may be used. ..
  • Patent Document 1 contains an active energy ray-curable component and a photopolymerization initiator having a wavelength of 390 nm and an optical path length of 10 mm in an acetonitrile solution having a concentration of 0.1% by mass and having an absorbance of 0.3 or more.
  • a pressure-sensitive adhesive sheet is produced from the solvent-type pressure-sensitive adhesive composition, and the pressure-sensitive adhesive sheet is bonded to an ultraviolet-shielding member to prepare a laminated body.
  • a method for producing a display body to be cured is disclosed.
  • Patent Document 2 describes an ultraviolet absorber via an ultraviolet curable pressure-sensitive adhesive sheet containing a photopolymerization initiator having an absorbance of 380 nm at a wavelength of 0.3 or more in an acetonitrile solution having a concentration of 0.1% by mass.
  • a method for manufacturing a display body in which a laminated body formed by laminating the contained display body constituent members is produced, and ultraviolet rays are irradiated through the display body constituent members containing the ultraviolet absorber to cure the adhesive sheet. There is.
  • Patent Document 3 describes an adhesive sheet for bonding an ultraviolet shielding member having an ultraviolet shielding property, wherein the adhesive sheet cures an active energy ray curable component and the active energy ray curable component (A).
  • An active energy ray which comprises an active energy ray-curable pressure-sensitive adhesive and has a substantial intensity emission in the wavelength region of 380 to 450 nm through the ultraviolet shielding member, is 1000 mJ / J / per to the pressure-sensitive adhesive sheet.
  • a pressure-sensitive adhesive sheet having a gel content of 70% or more and less than 100% when cured by irradiating with a light amount of cm 2 is disclosed.
  • Patent Document 4 is a method for manufacturing a display body including a display body component containing an ultraviolet absorber and a cured pressure-sensitive adhesive layer for laminating the display body component containing the ultraviolet absorber.
  • a method for manufacturing a display body is such that the pressure-sensitive adhesive layer is cured to form a cured pressure-sensitive adhesive layer by irradiating the display body constituent members with ultraviolet rays, and the gel content of the cured pressure-sensitive adhesive layer is 40% or more. It has been disclosed.
  • Japanese Patent No. 6360605 Japanese Patent No. 6420519 Japanese Patent No. 6438165 Japanese Patent No. 66676720
  • the polarizing plate used as an image display device member undergoes discoloration such as discoloration due to polyene conversion of the polyvinyl alcohol-based resin constituting the polarizing element and color loss of iodine in a moist heat environment.
  • discoloration such as discoloration due to polyene conversion of the polyvinyl alcohol-based resin constituting the polarizing element and color loss of iodine in a moist heat environment.
  • the color change of the polarizing plate in a moist heat environment due to the interaction between the polarizing plate and the photocurable pressure-sensitive adhesive sheet. May be promoted. Therefore, even in the in-vehicle image display device and the like, excellent durability in a high temperature and high humidity environment is required.
  • Patent Documents 1 to 4 when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component, the light can be cured by light in a wavelength range that can pass through the ultraviolet shielding component, and the temperature and humidity are severe.
  • a pressure-sensitive adhesive sheet in which appearance defects such as foaming and peeling are not observed even in an environment is disclosed, and as the photopolymerization initiator used, only an acylphosphine oxide-based photopolymerization initiator is exemplified.
  • the pressure-sensitive adhesive sheets disclosed in Patent Documents 1 to 4 do not mention the problem of discoloration of the polarizing plate in a harsh high temperature and high humidity environment.
  • the present invention can be photocured by light in a wavelength range that can pass through an ultraviolet shielding component when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component, and is polarized even in a harsh high temperature and high humidity environment.
  • a laminate comprising a photocurable pressure-sensitive adhesive sheet and a polarizing plate, in which discoloration of the plate, foaming, peeling and other appearance defects are not observed.
  • the present inventor uses a photopolymerization initiator capable of generating radicals by visible light as a photocurable pressure-sensitive adhesive sheet, and an acylphosphine oxide-based photopolymerization initiator contained in the pressure-sensitive adhesive layer. It has been found that the above-mentioned problems can be solved by using a phenylglycilate-based photopolymerization initiator as little as possible.
  • the gist of the present invention is the following [1] to [14].
  • [1] [I] A laminate laminated in a layer structure of a polarizing plate / a photocurable pressure-sensitive adhesive sheet.
  • the polarizing plate has a layer structure in which both sides of the polarizing element are laminated with a protective film.
  • the distance ( ⁇ ) between the photocurable adhesive sheet and the polarizing element is 80 ⁇ m or less.
  • the photocurable pressure-sensitive adhesive sheet is formed from a photo-curable pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer and a photopolymerization initiator (A), and [IV-2]
  • the light transmittance at a wavelength of 390 nm is less than 90%, and the light transmittance at a wavelength of 410 nm is 80% or more.
  • the total concentration of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition as the photopolymerization initiator (A) is 0. 5% by mass or less, Laminated body.
  • the photopolymerization initiator (A) contains at least one photopolymerization initiator selected from the group consisting of an ⁇ -aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator.
  • the photocurable pressure-sensitive adhesive composition contains a trifunctional or higher polyfunctional (meth) acrylate and / or a silane coupling agent.
  • the difference between the gel fraction G1 before light irradiation and the gel fraction G2 after light irradiation is 10% or more, [1] to The laminate according to any one of [11].
  • the laminated structure according to any one of [1] to [13] is a laminated structure cured by visible light.
  • the laminate of the present invention can be cured by visible light, the polarizing plate does not discolor even in a harsh high temperature and high humidity environment, and appearance defects such as foaming and peeling can be suppressed.
  • (meth) acrylic means acrylic or methacrylic
  • (meth) acryloyl means acryloyl or methacrylic acid
  • (meth) acrylate means acrylate or methacrylate.
  • the "(meth) acrylic acid ester (co) polymer” is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate-based monomer, and is referred to as a "(co) polymer”. Means to include polymers and copolymers.
  • the term "sheet” is not particularly distinguished from “film” and “tape”, but is described as a meaning including these.
  • X to Y (X and Y are arbitrary numbers)
  • it means “X or more and Y or less” and “preferably larger than X” or “preferably larger than X”. It also includes the meaning of "smaller than Y”.
  • X or more (X is an arbitrary number) or "Y or less” (Y is an arbitrary number)
  • "X and / or Y (X and Y are arbitrary configurations)” means at least one of X and Y, and means three types of X only, Y only, and X and Y. Is what you do.
  • the laminate of the present invention (hereinafter, may be referred to as “the present laminate”) is a laminate laminated in a layer structure of a photocurable pressure-sensitive adhesive sheet / polarizing plate.
  • the laminated body in which the other constituent members (X) are laminated via the photocurable adhesive sheet is mainly used for an in-vehicle image display device.
  • the photocurable adhesive sheet is attached to the adherend, then cured by irradiation with ultraviolet rays, and then attached to the adherend.
  • a glass cover member or a resin cover member that shields ultraviolet rays may be used because the polarizing plate or the like is easily deteriorated by ultraviolet rays. Therefore, the photocurable pressure-sensitive adhesive sheet constituting the present laminate, which is mainly used for an in-vehicle image display device, has visible light curability that can be cured by visible light instead of ultraviolet light.
  • the photocurable pressure-sensitive adhesive sheet is formed from a photo-curable pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer and a photopolymerization initiator (A) that generates a radical by visible light.
  • a photopolymerization initiator (A) the amount of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition is small.
  • each component contained in the photocurable pressure-sensitive adhesive composition will be described.
  • (Meta) acrylic acid ester (co) polymer As the (meth) acrylic acid ester (co) polymer used in the photocurable pressure-sensitive adhesive composition, for example, in addition to the homopolymer of alkyl (meth) acrylate, a monomer component copolymerizable therewith is copolymerized. The copolymer obtained by this can be mentioned. Of these, the (meth) acrylic acid ester copolymer is preferable.
  • Examples of the (meth) acrylic acid ester copolymer include an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms and a monomer component capable of copolymerizing with the alkyl (meth) acrylate, for example, (a) a carboxy group-containing monomer. , (B) hydroxyl group-containing monomer, (c) amino group-containing monomer, (d) epoxy group-containing monomer, (e) amide group-containing monomer, (f) vinyl monomer, and (g) macromonomer. Examples thereof include a copolymer with a monomer component containing one or more monomers.
  • a copolymer component containing an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, (e) an amide group-containing monomer, and (g) a macromonomer is preferable.
  • alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group examples include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and pentyl.
  • Examples thereof include alicyclic alkyl (meth) acrylates such as nyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate. These may be used alone or in combination of two or more. Of these, linear and branched alkyl (meth) acrylates having an alkyl group having 6 to 14 carbon atoms are preferable, and lauryl (meth) acrylate and 2-ethylhexyl (meth) acrylate are more preferable.
  • the content of the alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group is usually 30 to 90% by mass, preferably 35 to 88% by mass, more preferably 35 to 88% by mass in all the monomer components of the copolymer. Is 40 to 85% by mass, particularly preferably 55 to 85% by mass. If the content is too small, the hydrophobicity tends to decrease and it tends to be difficult to suppress water absorption, and if it is too large, the polarity tends to decrease and the adhesive strength tends to decrease.
  • Examples of the (a) carboxy group-containing monomer include (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, and 2- (meth).
  • Acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxypropyl phthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (Meta) acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid and the like can be mentioned. These may be used alone or in combination of two or more.
  • the content of the (a) carboxy group-containing monomer is usually 10% by mass or less, preferably 8% by mass or less, and particularly preferably 5% by mass or less in all the monomer components of the copolymer.
  • (B) Hydroxyl group-containing monomer examples include hydroxy such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate.
  • Alkyl (meth) acrylate and the like can be mentioned. These may be used alone or in combination of two or more.
  • the content of the hydroxyl group-containing monomer (b) is usually 30% by mass or less, preferably 25% by mass or less, and particularly preferably 20% by mass or less in all the monomer components of the copolymer.
  • Examples of the (c) amino group-containing monomer include aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, and aminoisopropyl (meth) acrylate, and N. -N, N-dialkylaminoalkyl (meth) acrylates such as alkylaminoalkyl (meth) acrylates, N, N-dimethylaminoethyl (meth) acrylates, N, N-dimethylaminopropyl (meth) acrylates and the like can be mentioned. can. These may be used alone or in combination of two or more.
  • the content of the (c) amino group-containing monomer is usually 20% by mass or less, preferably 10% by mass or less, and particularly preferably 10% by mass or less in all the monomer components of the copolymer.
  • (D) Epoxy group-containing monomer examples include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate glycidyl ether. Can be mentioned. These may be used alone or in combination of two or more.
  • the content of the epoxy group-containing monomer (d) is usually 20% by mass or less, preferably 10% by mass or less in all the monomer components of the copolymer.
  • (E) Amide group-containing monomer examples include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth).
  • Acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, maleic acid amide, maleimide and the like can be mentioned. These may be used alone or in combination of two or more. Of these, (meth) acrylamide is preferable.
  • the content of the (e) amide group-containing monomer is usually 1 to 20% by mass, preferably 1.5 to 15% by mass from the viewpoint of obtaining excellent adhesive properties, in all the monomer components of the copolymer. Particularly preferably, it is 2 to 10% by mass.
  • Examples of the (f) vinyl monomer include compounds having a vinyl group in the molecule.
  • Examples of such compounds include vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl laurate, aromatic vinyl monomers such as styrene, chlorostyrene, chloromethylstyrene, ⁇ -methylstyrene and other substituted styrenes.
  • Polyalkylene glycol di (meth) acrylates and the like may be one kind or a combination of two or more kinds.
  • the content of the vinyl monomer (f) is usually 40% by mass or less, preferably 35% by mass or less, and particularly preferably 30% by mass or less in all the monomer components of the copolymer.
  • the (g) macromonomer is a polymer monomer having a terminal functional group and a high molecular weight skeleton component.
  • the (g) macromonomer is preferably a monomer having 20 or more carbon atoms in the side chain when it becomes a (meth) acrylic acid ester copolymer by copolymerization.
  • the macromonomer is introduced as a branch component of the (meth) acrylic acid ester copolymer, and the (meth) acrylic acid ester copolymer can be used as a graft copolymer. Further, the characteristics of the main chain and the side chain of the graft copolymer can be changed by selecting (g) the macromonomer and other monomers and the blending ratio.
  • Examples of the terminal functional group of the (g) macromonomer include a radical polymerization group such as a (meth) acryloyl group and a vinyl group, a hydroxy group, an isocyanate group, an epoxy group, a carboxy group, an amino group, an amide group and a thiol group. And other functional groups can be mentioned. Among them, those having a radically polymerizable group copolymerizable with other monomers are preferable, and (meth) acryloyl group is particularly preferable.
  • the terminal functional group may be contained at one or two or more, and one of them is particularly preferable. Further, the (g) macromonomer may have a functional group mentioned above in addition to the terminal functional group.
  • the skeleton component of the (g) macromonomer is preferably composed of a (meth) acrylic acid ester (co) polymer or a vinyl-based polymer, for example, an alkyl having 1 to 18 carbon atoms in the alkyl group. Examples thereof include a meta) acrylate, the (a) carboxy group-containing monomer, the (b) hydroxyl group-containing monomer, the (d) epoxy group-containing monomer, and the (e) amide group-containing monomer. These may be used alone or in combination of two or more. Among them, the skeleton component of (g) macromonomer preferably contains a hydrophobic monomer and a hydrophilic monomer as constituent units.
  • an alkyl ester having no polar group (excluding methyl (meth) acrylate) is preferable, and for example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl.
  • hydrophobic monomers other than the alkyl ester examples include vinyl monomers such as vinyl acetate, styrene, t-butyl styrene, ⁇ -methyl styrene, vinyl toluene, and alkyl vinyl monomers. These may be used alone or in combination of two or more.
  • methyl (meth) acrylate and an ester having a polar group are preferable, and for example, methyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) ( Hydroxyl-containing (meth) acrylates such as meta) acrylates, hydroxybutyl (meth) acrylates and glycerol (meth) acrylates, (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyl Oxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloy
  • alkoxypolyalkylene glycol (meth) acrylate such as (meth) acrylate, N, N-dimethylacrylamide, hydroxyethylacrylamide and the like. These may be used alone or in combination of two or more.
  • macromonomers (g) isobonyl (meth) acrylate and hydrophilic are used as hydrophobic monomers from the viewpoint that the macromonomers of the main chain and the side chains of the graft copolymer have an appropriate phase separation structure.
  • the monomer a macromonomer obtained by reacting methyl (meth) acrylate in a ratio of 1: 1 is preferable.
  • the glass transition temperature (Tg) of the (g) macromonomer is preferably higher than the glass transition temperature of the copolymerization component constituting the (meth) acrylic acid ester (co) polymer.
  • the glass transition temperature (Tg) of the (g) macromonomer affects the heating and melting temperature (hot melt temperature) of the photocurable pressure-sensitive adhesive composition, and thus is preferably 30 to 120 ° C. It is more preferably 40 to 110 ° C, and particularly preferably 50 to 100 ° C.
  • the glass transition temperature of the (g) macromonomer means the glass transition temperature of the macromonomer itself, and can be measured by a differential scanning calorimeter (DSC).
  • the obtained (meth) acrylic acid ester (co) polymer has a branch component at room temperature (25 ° C.). It is possible to maintain a state in which they are attracted to each other and physically cross-linked. Moreover, by heating to an appropriate temperature, the physical cross-linking can be dissolved and fluidity can be obtained. Therefore, when the adhesive sheet described later is formed, the sheet shape can be maintained without being cured. In order to obtain such physical properties, it is also preferable to adjust the molecular weight and content of the macromonomer.
  • the number average molecular weight of the (g) macromonomer is preferably 500 to 20000, more preferably 600 to 10000, still more preferably 800 to 8000, particularly preferably 1000 to 7000, and particularly preferably 1500 to. It is 6000.
  • the content of (g) macromonomer is preferably 5 to 30% by mass, more preferably 6 to 25% by mass, and particularly preferably 8 to 20% by mass in the total monomer components of the copolymer. be. If the content is too small, the physical cross-linking between the branch components tends to be too weak and the storage stability tends to deteriorate when placed at room temperature (25 ° C.), and if it is too high, the physical cross-linking between the branch components tends to be too strong. There is a tendency for the fluidity to deteriorate when heated.
  • the (meth) acrylic acid ester-based (co) polymer is an alkyl (meth) acrylate or an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, and a monomer component copolymerizable therewith, for example. It can be obtained by polymerizing according to conventionally known methods such as solution radical polymerization, suspension polymerization, bulk polymerization, and emulsification polymerization.
  • the weight average molecular weight of the (meth) acrylic acid ester-based (co) polymer thus obtained is usually 50,000 to 1,500,000, preferably 70,000 to 1,300,000, particularly preferably 100,000 to 1,200,000, and even more preferably. It is 150,000 to 1 million.
  • the weight average molecular weight is measured by the following method.
  • a gel permeation chromatography (GPC) analyzer (device name: HLC-8320GPC manufactured by Toso Co., Ltd.) was used as a measurement sample in which a (meth) acrylic acid ester-based (co) polymer was dissolved in tetrahydrofuran (THF). ) Is used to measure the molecular weight distribution curve under the following conditions, and the weight average molecular weight (Mw) is obtained.
  • GPC gel permeation chromatography
  • TSKguardcolumnHXL -Separation column TSKgelGMHXL (4) ⁇ Temperature: 40 °C ⁇ Injection amount: 100 ⁇ L ⁇ Polystyrene conversion ⁇ Solvent: THF ⁇ Flow velocity: 1.0 mL / min
  • the (meth) acrylic acid ester (co) polymer has an active energy ray crosslinkable structural site.
  • the active energy ray-crosslinkable structure is, for example, a part of a (meth) acrylic acid ester (co) polymer or a (meth) acrylic acid ester (co) in the presence of a photopolymerization initiator (A) described later. ) It is a structural part that can react with a curing component other than the polymer to form a crosslinked structure.
  • the active energy ray crosslinkable structural site includes, for example, a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group.
  • a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group.
  • a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group.
  • the polymer chain of the (meth) acrylic acid ester (co) polymer has a radically polymerizable functional group, the polymer chains can be directly polymerized even when the cross-linking agent is not contained.
  • a monomer having a functional group such as a hydroxyl group or a carboxy group is used as a copolymerization component (meth).
  • a compound having a functional group capable of reacting with this functional group and an unsaturated double bond is added to the unsaturated double.
  • the reaction may be carried out while maintaining the polymerizable property of the bond.
  • the photopolymerization initiator (A) contained in the photocurable pressure-sensitive adhesive composition can generate radicals by irradiation with visible light, light having wavelengths of at least 390 nm, 405 nm and 410 nm, for example, light in the wavelength region of 380 to 700 nm. It is a visible light initiator that is generated and serves as a starting point for the reaction of the (meth) acrylic acid ester (co) polymer.
  • the photo-curable pressure-sensitive adhesive composition can be cured by visible light.
  • the photopolymerization initiator (A) may generate radicals only by irradiation with visible light, or may also generate radicals by irradiation with light in a wavelength region other than the visible light region. You may.
  • the photopolymerization initiator (A) preferably has an extinction coefficient of 10 mL / (g ⁇ cm) or more at a wavelength of 405 nm, more preferably 15 mL / (g ⁇ cm) or more, and particularly preferably 25 mL / (g). ⁇ Cm) or more.
  • the absorption coefficient at a wavelength of 405 nm is equal to or higher than the above value, curing (crosslinking) can be sufficiently proceeded by irradiation with visible light.
  • the upper limit of the absorption coefficient at a wavelength of 405 nm is preferably 1 ⁇ 10 4 mL / (g ⁇ cm) or less, and more preferably 1 ⁇ 10 3 mL / (g ⁇ cm) or less. In the present invention, it may be used in combination with a photopolymerization initiator having an extinction coefficient of less than 10 mL / (g ⁇ cm) at a wavelength of 405 nm.
  • the photopolymerization initiator (A) is roughly classified into two types according to the radical generation mechanism, a cleavage-type photopolymerization initiator capable of cleaving and decomposing a single bond of the photopolymerization initiator itself to generate a radical, and a photoexcitation.
  • the initiator and the hydrogen donor in the system form an excitation complex, and the initiator is roughly classified into a hydrogen abstraction type photopolymerization initiator capable of transferring the hydrogen of the hydrogen donor.
  • the cleavage-type photopolymerization initiator decomposes to another compound when a radical is generated by light irradiation, and once excited, it loses its function as a reaction initiator. Therefore, it is preferable because it does not remain as an active species in the pressure-sensitive adhesive after the cross-linking reaction is completed and there is no possibility of causing unexpected photodegradation of the pressure-sensitive adhesive.
  • cleavage-type photopolymerization initiator examples include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one and 2-benzyl-2- (dimethylamino) -4'.
  • - ⁇ -Aminoacetophenone-based photopolymerization initiator such as morpholinobtyrophenone, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholi-4-yl-phenyl) -butane-1-one; bis (2,4,6-trimethylbenzoyl) -Phenylphosphinoxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide, bis (2,6- Dimethoxybenzoyl) Acylphosphine oxide-based photopolymerization initiator such as 2,4,4-trimethylpentylphosphine oxide; benzylketal-based photopolymerization initiator such as 2,2-dimethoxy-1,2-diphenylethane-1-one; 1-Hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl
  • an ⁇ -aminophenone-based photopolymerization initiator is preferable. Since the ⁇ -aminophenone-based photopolymerization initiator does not generate an acid when decomposed by light irradiation, it tends to be able to suppress discoloration of the polarizing plate. In the present invention, it is desired to avoid using the ⁇ -aminophenone-based photopolymerization initiator because the center wavelength of the light absorption peak is out of the visible light region and a defect of curing failure is presumed. When it was intentionally used, it was possible to effectively suppress the discoloration of the polarizing plate without such a problem.
  • the acylphosphine oxide-based photoinitiator and the phenylglycioxylate-based photoinitiator usually have the center wavelength of the light absorption peak at the visible light absorption peak and are poorly cured. Since it was used as a photopolymerization initiator from the viewpoint of less concern, in the present invention, the amount of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the pressure-sensitive adhesive sheet should be reduced. It was possible to suppress the discoloration of the polarizing plate.
  • acylphosphine oxide-based photopolymerization initiators acylphosphine oxide-based photopolymerization initiators, phenylglycilate-based photopolymerization initiators, and the like are decomposed to generate acids when radicals are generated by light irradiation. If this acid remains on the pressure-sensitive adhesive sheet after being bonded to the polarizing plate, it may act as a catalyst and cause discoloration due to polyene formation of the polyvinyl alcohol-based resin constituting the polarizing element.
  • an acylphosphine oxide-based photopolymerization initiator or a phenylglycilate-based photopolymerization initiator it is preferable not to use an acylphosphine oxide-based photopolymerization initiator or a phenylglycilate-based photopolymerization initiator, but the range does not affect the effect of the present invention (photocurable pressure-sensitive adhesive composition). 0.5% by mass or less) may be used.
  • Examples of the hydrogen abstraction type photopolymerization initiator include bis (2-phenyl-2-oxoacetic acid) oxybisethylene, phenylglycoxyacid methyl ester, and oxy-phenyl-acetylic acid 2- [2-oxo-.
  • a ketocoumarin-based photopolymerization initiator As the hydrogen abstraction type photopolymerization initiator, a ketocoumarin-based photopolymerization initiator is preferable.
  • the ketocoumarin-based photopolymerization initiator has sufficient visible light reactivity, yellowing can be adjusted to a practically acceptable level by adjusting the addition amount, and there is a tendency that discoloration of the polarizing plate can be suppressed.
  • the photopolymerization initiator (A) may contain at least one photopolymerization initiator selected from the group consisting of an ⁇ -aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator. preferable.
  • the photopolymerization initiator (A) is not limited to the substances listed above. Any one of the above-mentioned photopolymerization initiators (A) or a derivative thereof may be used, or two or more thereof may be used in combination. Further, in addition to the photopolymerization initiator (A), a substance that generates radicals only by irradiation with other light rays such as ultraviolet rays may be mixed.
  • the content of the photopolymerization initiator (A) in the photocurable pressure-sensitive adhesive composition is usually 0.1 to 10 parts by mass, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the (meth) acrylic acid ester (co) polymer. It is 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass.
  • the photocurable pressure-sensitive adhesive composition used in the present invention contains a cross-linking agent and / or a silane coupling agent in addition to the (meth) acrylic acid ester (co) polymer and the photopolymerization initiator (A). Is preferable.
  • the cross-linking agent is, for example, at least selected from a (meth) acryloyl group, an epoxy group, an isocyanate group, a carboxyl group, a hydroxy group, a carbodiimide group, an oxazoline group, an aziridine group, a vinyl group, an amino group, an imino group and an amide group.
  • a compound having one kind of crosslinkable functional group can be mentioned. These may be used alone or in combination of two or more.
  • the cross-linking agent the cross-linking functional group may be protected by a deprotectable protecting group, or the cross-linking agent may be chemically bonded to a (meth) acrylic acid ester (co) polymer.
  • a photopolymerizable compound having a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group, particularly a polyfunctional (meth) acrylate is preferable.
  • polyfunctional means having two or more (meth) acryloyl groups.
  • polyfunctional (meth) acrylate examples include 1,4-butaneerythritol di (meth) acrylate, glycerindi (meth) acrylate, neopentythritol glycol di (meth) acrylate, and glycering ricidyl ether di (meth) acrylate, 1.
  • 6-Hentaerythritol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate Neopentylglycolyl hydroxybivariate di (meth) acrylate, ⁇ -caprolactone adduct of neopenterythritol hydroxyvivariate (Meta) acrylate, tricyclodecandymethacrylate, tricyclodecanedimethanol di (meth) acrylate, bisphenol A polyethoxydi (meth) acrylate, bisphenol A polypropoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, ethylene glycol Bifunctional (meth) acrylate such as di (meth) acrylate; trimeritol propanthritoltrioxyethyl (meth) acrylate, ⁇ -caprolactone-modified tris (2-hydroxyethyl) isocyanur
  • examples thereof include (meth) acrylates having four or more functions.
  • examples of the polyfunctional (meth) acrylate include polyfunctional (meth) acrylics such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate.
  • examples include oligomers. These may be used alone or in combination of two or more. Of these, trifunctional or higher polyfunctional (meth) acrylates are preferred, trifunctional (meth) acrylates are more preferred, and propoxylated pentaerythritol tri (meth) acrylates are particularly preferred.
  • the content of the cross-linking agent is 0.5 to 50 parts by mass, particularly 1 to 40 parts by mass, and 5 to 30 parts by mass thereof with respect to 100 parts by mass of the (meth) acrylic acid ester (co) polymer. It is preferably a ratio. By setting such a content within the above range, the adhesive force and the cohesive force can be enhanced, which is preferable.
  • silane coupling agent The silane coupling agent is preferable because it can improve the adhesiveness, and above all, the adhesive force to the glass material.
  • silane coupling agent examples include a compound having a hydrolyzable functional group such as an alkoxy group as well as an unsaturated group such as a vinyl group, an acryloxy group and a methacryloxy group, an amino group and an epoxy group. can.
  • silane coupling agent examples include N- ( ⁇ -aminoethyl) - ⁇ -aminopropyltrimethoxysilane, N- ( ⁇ -aminoethyl) - ⁇ -aminopropylmethyldimethoxysilane, and ⁇ -aminopropyltriethoxysilane. , Gamma-glycidoxypropyltrimethoxysilane, ⁇ -methacryloxypropyltrimethoxysilane and the like. These may be used alone or in combination of two or more. Of these, ⁇ -glycidoxypropyltrimethoxysilane is preferable from the viewpoints of good adhesiveness and less discoloration such as yellowing.
  • the content of the silane coupling agent is usually 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester (co) polymer. By setting such a content within the above range, it is preferable because the problem of whitening can be avoided and the adhesive strength can be enhanced.
  • a coupling agent such as an organic titanate compound can be effectively utilized in addition to the silane coupling agent.
  • Other components of the photocurable pressure-sensitive adhesive composition include, for example, a light stabilizer, an ultraviolet absorber, a metal deactivating agent, a metal corrosion inhibitor, an antiaging agent, an antistatic agent, a hygroscopic agent, and foaming.
  • Various additives such as agents, defoaming agents, inorganic particles, viscosity modifiers, tackifier resins, photosensitizers, fluorescent agents, reaction catalysts (tertiary amine compounds, quaternary ammonium compounds, tin laurate compounds) Etc.) etc. may be included.
  • other known components to be blended in a normal pressure-sensitive adhesive composition may be appropriately contained. These other components may be used alone or in combination of two or more.
  • the photocurable pressure-sensitive adhesive composition may contain, for example, a (meth) acrylic acid ester (co) polymer, a photopolymerization initiator (A), preferably a cross-linking agent, a silane coupling agent, and if necessary, other materials.
  • A photopolymerization initiator
  • Each is obtained by mixing a predetermined amount.
  • a heat treatment step may be added at the time of producing the photocurable pressure-sensitive adhesive composition. In this case, it is desirable to mix each component of the photo-curable pressure-sensitive adhesive composition in advance and then perform the heat treatment. Further, in the above-mentioned mixing, a masterbatch obtained by concentrating various mixed components may be used.
  • the mixing method is not particularly limited, and for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressurized kneader, a three-roll, a two-roll, or the like can be used.
  • a universal kneader a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressurized kneader, a three-roll, a two-roll, or the like
  • each component of the photocurable pressure-sensitive adhesive composition When each component of the photocurable pressure-sensitive adhesive composition is mixed, it may be mixed using a solvent if necessary, or it may be mixed as a solvent-free system containing no solvent.
  • the photocurable pressure-sensitive adhesive sheet is formed from the photo-curable pressure-sensitive adhesive composition.
  • the pressure-sensitive adhesive sheet has a single-layer structure with only one layer, it has a multi-layer structure with two or more layers. Although it may be preferable, a multi-layer structure having two or more layers is preferable. Further, in the case of a multi-layer structure, at least the outermost layer may be formed from the photocurable pressure-sensitive adhesive composition, but all layers may be formed from the photo-curable pressure-sensitive adhesive composition. ..
  • the photo-curable pressure-sensitive adhesive composition may be applied.
  • the method for applying the photocurable pressure-sensitive adhesive composition is not particularly limited as long as it is a general coating method, and examples thereof include roll coating, die coating, gravure coating, comma coating, and screen printing. Can be mentioned.
  • the thickness ( ⁇ ) of the photocurable pressure-sensitive adhesive sheet is preferably 50 to 500 ⁇ m, more preferably 70 to 400 ⁇ m, and particularly preferably 100 to 300 ⁇ m.
  • the photocurable pressure-sensitive adhesive sheet thus formed has photocurability that is cured by irradiating with light.
  • the photocurable pressure-sensitive adhesive sheet may be one that has been cured (also referred to as "temporary curing") in a state where there is room for photo-curing, or has not yet been cured and is photo-cured. It may be uncured (referred to as "uncured") having a property. If the photocurable pressure-sensitive adhesive sheet to be formed is a temporary-cured one or an uncured one, the photo-curable pressure-sensitive adhesive sheet is attached to an adherend and then the photo-curable pressure-sensitive adhesive sheet is photo-cured (). It can also be referred to as "main curing"), and as a result, the cohesive force can be increased and the adhesiveness can be enhanced.
  • the gel content of the pressure-sensitive adhesive sheet may be set to 60% or less by irradiating with light.
  • the photocurable adhesive sheet is left as an adhesive sheet with a release sheet laminated with a release sheet in an unused state before being attached to an adherend, and the release sheet is peeled off when used. You may use it.
  • the release sheet is usually laminated on both sides of a photocurable pressure-sensitive adhesive sheet.
  • the pressure-sensitive adhesive sheet with a release sheet is produced, for example, by applying the photocurable pressure-sensitive adhesive composition on the release sheet to form a pressure-sensitive adhesive layer, and then laminating another release sheet. be able to.
  • a known release sheet can be appropriately used, and for example, a polyester resin, a polyolefin resin, a polycarbonate resin, a polystyrene resin, an acrylic resin, a triacetyl cellulose resin, and a fluorine resin can be used.
  • a sheet made of the above, which is coated with a silicone resin and subjected to a mold release treatment, a mold release paper, or the like can be appropriately selected and used. These may be used alone or in combination of two or more.
  • the release sheet preferably has a light transmittance of 40% or less at a wavelength of 410 nm or less, more preferably 30% or less, and particularly preferably 20%.
  • the light transmittance of the release sheet at a wavelength of 410 nm or less is not more than the above-mentioned numerical value, it is possible to effectively prevent photopolymerization by visible light during storage of the adhesive sheet or the like.
  • a release sheet having a light transmittance of 40% or less at a wavelength of 410 nm or less that is, a sheet having an action of partially blocking the transmission of visible light and ultraviolet light
  • the following (1) to (1) to ( 7) can be mentioned.
  • a slightly adhesive resin having removability is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin, and an ultraviolet absorber is applied to the other surface.
  • Laminated sheet with an ultraviolet absorbing layer made by applying the containing paint.
  • a slightly adhesive resin having removability is applied to a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin containing an ultraviolet absorber.
  • a paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin to provide an ultraviolet absorbing layer, and the ultraviolet absorbing layer is further provided.
  • a paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin to provide an ultraviolet absorbing layer, and the other surface is re-coated.
  • Laminated sheet coated with a slightly adhesive resin with peelability (7)
  • the other side of the resin film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin coated with a slightly adhesive resin having a removability on one surface, and a separately prepared resin film are subjected to ultraviolet rays.
  • the thickness of the release sheet is not particularly limited, but from the viewpoint of workability and handleability, it is preferably 25 to 500 ⁇ m, more preferably 38 to 250 ⁇ m, and particularly preferably 50 to 200 ⁇ m.
  • one release sheet is different even if it has the same laminated structure, material, and thickness as the other release sheet. It may have a laminated structure, a material, and a thickness. Further, a release sheet having different peeling forces between one release sheet and the other release sheet may be used.
  • the release sheet may have other layers such as an antistatic layer, a hard coat layer, an anchor layer, etc., if necessary.
  • an adhesive sheet with a release sheet By laminating another release sheet on the formed adhesive layer, an adhesive sheet with a release sheet can be obtained.
  • the photo-curable pressure-sensitive adhesive composition is applied onto a base material sheet or a release sheet to form a first pressure-sensitive adhesive sheet.
  • a method of forming a second pressure-sensitive adhesive sheet and then bonding the coated surfaces to each other, the photocurable pressure-sensitive adhesive composition is coated with a multi-layer coating or co-extrusion molding to form a first pressure-sensitive adhesive sheet and a second pressure-sensitive adhesive. It can be manufactured by a method of forming sheets at the same time.
  • the photo-curable pressure-sensitive adhesive composition is directly applied to a polarizing plate or an adherend (another constituent member (X)) without using a release sheet as described above. It may be applied and formed into a sheet, or the photocurable pressure-sensitive adhesive composition may be directly extruded to form a photo-curable pressure-sensitive adhesive sheet. Further, the present pressure-sensitive adhesive sheet may be formed by injecting the photo-curable pressure-sensitive adhesive composition into a mold, or the photo-curable pressure-sensitive adhesive composition may be formed between the polarizing plate and another constituent member (X) which is an adherend. May be used as an embodiment of a photocurable pressure-sensitive adhesive sheet by directly filling with.
  • the photocurable pressure-sensitive adhesive sheet thus obtained contains an acylphosphine oxide-based photopolymerization initiator and a phenylglycilate-based photopolymerization initiator as the photopolymerization initiator (A) in the photocurable pressure-sensitive adhesive composition.
  • the total concentration is 0.5% by mass or less, preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less.
  • the lower limit is, of course, 0% by mass.
  • the photocurable pressure-sensitive adhesive sheet is polarized by an acid by reducing the contents of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator, which are decomposed by light irradiation and generate an acid. It is possible to suppress discoloration of the plate.
  • the photocurable pressure-sensitive adhesive sheet has a multi-layer structure of two or more layers, the acylphosphine oxide-based photopolymerization initiator and phenylglioxy contained in the photocurable pressure-sensitive adhesive composition forming a layer in contact with the polarizing plate.
  • the concentration of the rate-based photopolymerization initiator may be within the above range.
  • the photocurable pressure-sensitive adhesive sheet has a light transmittance of less than 90% at a wavelength of 390 nm and a light transmittance of 80% or more at a wavelength of 410 nm.
  • a photocurable pressure-sensitive adhesive composition containing a photopolymerization initiator having absorption in the ultraviolet to visible light region with a wavelength of around 400 nm the light absorption of the photopolymerization initiator is large, and light rays at a wavelength of 390 nm derived from the absorption are large.
  • the lower the transmittance the better the photosensitivity and the easier the curing progresses.
  • the photocurable adhesive sheet will be colored yellow and difficult to use in an image display device.
  • the light transmittance at a wavelength of 390 nm is less than 90%, sufficient visible light curability can be ensured, which is preferable.
  • the light transmittance at a wavelength of 410 nm is 80% or more, an optical member requiring transparency is required. It is possible to achieve a sufficiently low yellow index value (YI value) required for bonding.
  • the light transmittance of the photocurable pressure-sensitive adhesive sheet at a wavelength of 390 nm is less than 90%, preferably 88% or less.
  • the light transmittance of the photocurable pressure-sensitive adhesive sheet at a wavelength of 410 nm is 80% or more, preferably 85% or more, and particularly preferably 90% or more.
  • the base of the absorption peak reaches 390 nm, whereas the base of the absorption peak is sufficiently reached.
  • At least one selected from the group consisting of an ⁇ -aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator having an absorption peak characteristic in which the absorption peak becomes small at 410 nm may be used.
  • the method is not limited to this method.
  • the photocurable pressure-sensitive adhesive sheet can be cured even by light irradiation having a wavelength of 390 to 410 nm.
  • the photocurable adhesive sheet has a yellow index value measured based on JIS K7103 after being irradiated with high-pressure mercury lamp UV light so that the integrated light amount is 3000 (mJ / cm 2 ). , 2.0 or less, more preferably 1.9 or less.
  • the gel fraction G1 of the photocurable pressure-sensitive adhesive sheet before light irradiation is usually 50% or less, preferably 40% or less, and particularly preferably 20% or less.
  • the lower limit is 0%.
  • the gel fraction is determined by the following method.
  • the mass (mass before immersion) of the photocurable pressure-sensitive adhesive sheet is measured, wrapped in a bag shape with SUS mesh (# 200), immersed in ethyl acetate, and stored in a dark place at 23 ° C. for 24 hours. Then, the package is taken out and heated at 70 ° C. for 4.5 hours to evaporate the adhered ethyl acetate, and the mass (mass after immersion) of the remaining photocurable adhesive sheet is measured, and the gel content is measured from the following formula. Find the rate.
  • Gel fraction (%) [(mass after immersion) / (mass before immersion)] ⁇ 100
  • the residual catalyst is sufficiently removed during the polymerization of the (meth) acrylic acid ester (co) polymer and the processing of the photocurable pressure-sensitive adhesive sheet, or
  • a polymerization inhibitor, an antioxidant, or the like it is sufficient to prevent an unintended curing (crosslinking) reaction due to heat, light, or the like from proceeding before the main curing.
  • the integrated light amount of the light to be irradiated for the temporary curing may be sufficiently small so that the uncrosslinked component is sufficiently large.
  • the method is not limited to this method.
  • the gel fraction G2 after the light irradiation Is usually 40 to 100%, preferably 50 to 100%, and particularly preferably 60 to 100%.
  • the gel fraction G2 after light irradiation of the photocurable adhesive sheet is within the above range, there is a tendency that appearance defects such as foaming and peeling are not observed even in a harsh high temperature and high humidity environment.
  • the difference between the gel fraction G1 before light irradiation and the gel fraction G2 after light irradiation is preferably 10% or more. , More preferably 30% or more, and particularly preferably 60% or more.
  • the upper limit is usually 100%.
  • a photopolymerization initiator (A) having absorption at a wavelength of 405 nm may be used.
  • the method is not limited to this method.
  • the above-mentioned "having ultraviolet shielding property” means that the light transmittance at a wavelength of 365 nm is 10% or less and the light transmittance at a wavelength of 405 nm is 60% or more.
  • an ultraviolet shielding member for example, "Iupilon sheet MR58, thickness 1.0 mm” manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.
  • the "integrated light amount at a wavelength of 405 nm” is the total amount of irradiation energy received per unit area, and among the light emitted by a high-pressure mercury lamp or the like, the ultraviolet integrated light meter “UIT-250" (Ushio Denki Co., Ltd.) ) And the total amount of light irradiation energy measured using the photoreceiver "UVD-C405" (manufactured by Ushio Denki Co., Ltd.). It refers to the integrated amount of light in the wavelength range according to (having a light sensitivity with a wide base). More specifically, it refers to the integrated light intensity obtained in accordance with the method described in the examples.
  • the photocurable pressure-sensitive adhesive sheet is laminated in the layer structure of the polarizing plate / photo-curable pressure-sensitive adhesive sheet, and the one having the laminated structure is the present laminated body.
  • the polarizing plate is not particularly limited.
  • a triacetyl cellulose-based resin film or an acrylic resin film has both sides of a polyvinyl alcohol-based resin layer (polarizer) in which iodine compound molecules are adsorbed and oriented on a polyvinyl alcohol-based resin film.
  • polarizer polyvinyl alcohol-based resin layer
  • Polyester-based resin film, cycloolefin polymer-based resin film, and other protective films laminated laminated.
  • those in which both sides of the stator are laminated with a triacetyl cellulose-based resin film are preferable because they are not stretched and therefore have excellent optical isotropic properties.
  • the protective film preferably has a moisture permeability of 1 to 1000 (g / m 2 / day), particularly 5 to 800 (g), from the viewpoint of preventing discoloration of the polarizing element due to the infiltration of water. / M 2 / day), more preferably 10 to 600 (g / m 2 / day).
  • the distance ( ⁇ ) between the photocurable pressure-sensitive adhesive sheet and the polarizing element is 80 ⁇ m or less, preferably 10 to 80 ⁇ m, and more preferably 10 to 50 ⁇ m.
  • the distance ( ⁇ ) between the photocurable pressure-sensitive adhesive sheet and the polarizing element is defined as the photocuring from the surface of the polarizing element (polyvinyl alcohol-based resin film layer) on the surface to which the photocurable pressure-sensitive adhesive sheet of the polarizing plate is bonded. The distance to the surface where the adhesive sheet is in contact with the polarizing plate.
  • the ratio ( ⁇ / ⁇ ) of the distance ( ⁇ ) between the pressure-sensitive adhesive sheet and the polarizing element and the thickness ( ⁇ ) of the photocurable pressure-sensitive adhesive sheet is 0.1 to 0 from the viewpoint of suppressing discoloration of the polarizing plate. 5 is preferable, more preferably 0.1 to 0.4, and particularly preferably 0.1 to 0.3.
  • thinning of the display has been aimed at in order to reduce the weight
  • thinning of the polarizing plate has also been aimed at. Even if the distance ( ⁇ ) from the polarizing element is short, the above range is preferable in that discoloration of the polarizing plate can be suppressed.
  • the other component (X) As the other component (X), a member having a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm, that is, a member having an ultraviolet light-shielding property (ultraviolet rays). Light-shielding cover material) is preferable. If the other component (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm, it sufficiently blocks (cuts) the transmission of ultraviolet rays. The photodeterioration of the other constituent member (X) itself and the polarizing plate located via the photocurable pressure-sensitive adhesive sheet is suppressed, and the yellow index value (YI value) is reduced to the level required for the laminated body. be able to.
  • Examples of such other constituent members (X) include those having a resin material as a main component and adjusted to have the light transmittance by using an ultraviolet absorber.
  • the resin material examples include a material containing a polycarbonate resin or an acrylic resin as a main component resin.
  • the "main component resin” means a resin having the largest mass content among the resins constituting the other constituent member (X).
  • the method of laminating the other component (X) via the photocurable pressure-sensitive adhesive sheet is not particularly limited, and either the polarizing plate or the other component (X) is laminated with the photo-curable pressure-sensitive adhesive sheet. After that, the other may be laminated with the photocurable pressure-sensitive adhesive sheet, or the polarizing plate and the other constituent member (X) may be laminated with the photocurable pressure-sensitive adhesive sheet at the same time.
  • the laminated body thus obtained becomes a laminated structure in which the photocurable adhesive sheet is cured by irradiating with visible light thereafter.
  • the laminated structure can be used mainly as a component of an image display device for an automobile.
  • Example 1 Manufacturing of photocurable adhesive sheet
  • ⁇ -Amino as a photopolymerization initiator with respect to 1 kg of an acrylic graft copolymer (mass average molecular weight: 160,000) obtained by randomly copolymerizing 40 parts by mass of 2-ethylhexyl acrylate and 2.8 parts by mass of acrylamide.
  • Acetphenone-based 2-benzyl-2- (dimethylamino) -4'-morpholinobtyrophenone (IGM: Omnirad369) 15 g, propoxylated pentaerythritol triacrylate as a cross-linking agent (NK ester ATM-4PL, manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 g and 1.5 g of 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM403) as a silane coupling agent were added and uniformly mixed to obtain a photocurable pressure-sensitive adhesive composition.
  • NK ester ATM-4PL manufactured by Shin-Nakamura Chemical Co., Ltd.
  • 3-glycidyloxypropyltrimethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd .: KBM403
  • the photocurable pressure-sensitive adhesive composition is formed into a sheet having a thickness of 150 ⁇ m on a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 ⁇ m) whose surface has been peeled off.
  • a polyethylene terephthalate film manufactured by Mitsubishi Chemical Corporation, Diafoil MRQ, thickness 75 ⁇ m
  • whose surface has been peeled off was coated to produce a photocurable adhesive sheet with a release sheet.
  • a polarizing plate As a polarizing plate, an adhesive layer, a triacetyl cellulose-based resin film, and a coat layer are laminated in this order on both sides of a polyvinyl alcohol-based resin film (12 ⁇ m) in which iodine is adsorbed and oriented, and the surface of the polyvinyl alcohol-based resin film layer is formed on the surface. , A polarizing plate to which the pressure-sensitive adhesive sheet was attached was used at a depth of 35 ⁇ m from the outermost surface.
  • a polycarbonate resin plate having an ultraviolet shielding property (thickness 1.0 mm, light transmittance of 0% at 365 nm, light transmittance of 83% at 405 nm, Mitsubishi Gas Chemical Company, Iupilon sheet) MR58) was used.
  • the photo-curable pressure-sensitive adhesive sheet is a polarizing plate from the surface of the polyvinyl alcohol-based resin film layer on the surface to which the photo-curable pressure-sensitive adhesive sheet of the polarizing plate is bonded.
  • the distance to the surface in contact with the light was 35 ⁇ m.
  • the ratio of the distance between the photocurable pressure-sensitive adhesive sheet and the polarizing element to the thickness of the photo-curable pressure-sensitive adhesive sheet was 0.2.
  • Example 2 As a photopolymerization initiator, 15 g of ⁇ -aminoacetophenone-based 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholinophenyl) -butane-1-one (IGM: Omnirad379) was used. A laminated body of a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained in the same manner as in Example 1.
  • Example 3 Examples except that 15 g of ⁇ -aminoacetophenone-based 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (IGM: Omnirad907) was used as the photopolymerization initiator.
  • IGM ⁇ -aminoacetophenone-based 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one
  • IGM Omnirad907
  • Example 4 A photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / photo-curable pressure-sensitive adhesive in the same manner as in Example 1 except that 5 g of a ketocoumarin-based ketocoumarin derivative (manufactured by IGM: Esacure3644) was used as the photopolymerization initiator. A laminated body of a sheet / polycarbonate resin plate having an ultraviolet shielding property was obtained.
  • Example 5 Acylphosphinoxide-based ethyl phosphinate (manufactured by IGM: Omnirad TPO-L) 3 g as a photopolymerization initiator, and pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) as a cross-linking agent. , NK Ester ATMM-3L) 50 g) was used, and the photocurable pressure-sensitive adhesive composition obtained in the same manner as in Example 1 was used as an intermediate layer pressure-sensitive adhesive sheet (1) (thickness: 200 ⁇ m).
  • the PET films on both sides of the adhesive sheet for the intermediate layer are sequentially peeled off and removed, and the adhesive surfaces of the adhesive sheets (2) and ('2') for the surface layer are sequentially bonded to both surfaces, and (2) / (1) /.
  • a 250 ⁇ m-thick photocurable pressure-sensitive adhesive sheet with a release sheet made of ('2') was produced. Then, in the same manner as in Example 1, a laminated body of a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
  • Example 4 A photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate were obtained in the same manner as in Example 1 except that 15 g of phenylglycilate-based methyl benzoyllate (manufactured by IGM: Omnirad MBF) was used as the photopolymerization initiator. / A laminated body of a photocurable adhesive sheet / a polycarbonate resin plate having an ultraviolet shielding property was obtained.
  • the polarizing plate / is the same as in Comparative Example 1 except that the surface of the polyvinyl alcohol-based resin film layer is located at a depth of 90 ⁇ m from the outermost surface of the polarizing plate to which the pressure-sensitive adhesive sheet is attached.
  • a laminate of a photocurable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
  • the release sheet is peeled off from the photocurable adhesive sheet with a release sheet, and a spectrophotometer (UV2000 manufactured by Shimadzu Corporation) is used to spectrally transmit the photocurable adhesive sheet at a wavelength of 300 to 800 nm. The rate (% T) was measured.
  • UV2000 manufactured by Shimadzu Corporation
  • Yellow index value (YI value)
  • the release sheet is peeled off from the photocurable adhesive sheet with a release sheet, and after irradiating with high-pressure mercury lamp UV light so that the integrated light amount becomes 3000 (mJ / cm 2 ), a spectrocolorimeter (manufactured by Suga Test Instruments Co., Ltd.) )
  • the yellow index value (YI value) was measured based on JIS K7103 using "SC-T".
  • the integrated light amount at 405 nm from the polycarbonate resin plate side having ultraviolet shielding property using a high pressure mercury lamp. After irradiating with light so as to be 3000 (mJ / cm 2 ), the cured photocurable pressure-sensitive adhesive sheet portion was scraped off with a spatula, and the gel fraction G2 after light irradiation was determined by the same method.
  • an acylphosphine oxide-based photopolymerization initiator and a phenylglycilate-based photopolymerization initiator are added as photopolymerization initiators to the photocurable pressure-sensitive adhesive composition forming a layer in contact with the polarizing plate.
  • the photocurable pressure-sensitive adhesive sheet was sufficiently cured by light irradiation from the laminated body side of the polycarbonate-based resin plate having an ultraviolet shielding property, which was not used. Further, the laminate after light irradiation does not cause decolorization of the polarizing plate even after exposure at 85 ° C., 85% RH, and 1000 hours, and good moisture resistance and heat reliability without appearance defects such as foaming and peeling can be obtained.
  • the photocurable pressure-sensitive adhesive sheet was sufficiently cured by light irradiation from the laminated body side of the polycarbonate-based resin plate having an ultraviolet shielding property, which was not used. Further, the laminate after light irradiation does not cause decolorization of the
  • the laminate of the polarizing plate / photocurable pressure-sensitive adhesive sheet / UV-shielding polycarbonate-based resin plate has an acylphosphine oxide-based photopolymerization initiator or a phenylglycilate-based photopolymerization on the pressure-sensitive adhesive layer. Since the initiator was contained in a specific amount or more, the laminate after light irradiation had no appearance defects such as foaming and peeling after exposure at 85 ° C., 85% RH, and 1000 hours, but significant discoloration occurred in the polarizing plate.
  • the acylphosphine oxide-based photopolymerization is started on the photocurable pressure-sensitive adhesive composition.
  • the photocurable pressure-sensitive adhesive sheet of Comparative Example 1 containing a specific amount or more of the agent was used, discoloration did not occur in the polarizing plate, and good results were obtained. From this, it is shown that the present invention can be suitably used particularly in a configuration in which the distance between the photocurable pressure-sensitive adhesive sheet and the polarizing element is short.
  • the laminate of the present invention is cured by visible light and can suppress appearance defects such as discoloration, foaming and peeling of the polarizing plate even under high temperature and high humidity, and is therefore suitable for an in-vehicle image display device component. Can be used.

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Abstract

Provided is a laminate which can be photocured by visible light and which does not exhibit appearance defects such as discoloration, bubbling, or exfoliation of a polarizing plate even in extreme high-temperature, high-humidity environments, [I] the laminate being obtained by laminating a polarizing plate and a photocurable adhesive sheet in a layered configuration, wherein: [II] the polarizing plate has a layered configuration in which both surfaces of a polarizer are laminated with a protective film; [III] the distance (α) between the photocurable adhesive sheet and the polarizer is no more than 80 μm; [IV-1] the photocurable adhesive sheet is formed from a photocurable adhesive agent composition including a (meth)acrylic acid ester (co)polymer and a photopolymerization initiator (A); [IV-2] the light transmittance at a wavelength of 390 nm is less than 90% and the light transmittance at a wavelength of 410 nm is at least 80%; and [IV-3] the total concentration of an acylphosphine oxide-based photopolymerization initiator and a phenylglyoxylate-based photopolymerization initiator, which are included as the photopolymerization initiator (A) in the photocurable adhesive agent composition, is no more than 0.5 mass%.

Description

積層体及び積層構造体Laminated body and laminated structure
　本発明は、紫外線を透過しない紫外線カット性を有する樹脂部材を貼合するために用いる粘着シートを備える積層体であって、光を照射することにより硬化する性能（以下、「光硬化性」と称する）を備えている光硬化性粘着シートを有する積層体に関する。 The present invention is a laminate provided with an adhesive sheet used for bonding a resin member having an ultraviolet ray blocking property that does not transmit ultraviolet rays, and has a performance of being cured by irradiating with light (hereinafter referred to as "photocuring property"). It relates to a laminate having a photocurable pressure-sensitive adhesive sheet (referred to as).
　近年、画像表示装置の視認性を向上させるために、液晶ディスプレイ（ＬＣＤ）、プラズマディスプレイ（ＰＤＰ）、エレクトロルミネッセンスディスプレイ（ＥＬＤ）等の画像表示パネルと、その前面側（視認側）に配置する保護パネルやタッチパネル部材との間の空隙を接着剤で充填することにより、入射光や表示画像からの出射光の空気層界面での反射を抑えることが行われている。このような画像表示装置構成部材間の空隙を粘着剤で充填する方法として、画像表示装置構成部材間の空隙を、粘着シートを用いて充填する方法が知られている。 In recent years, in order to improve the visibility of an image display device, an image display panel such as a liquid crystal display (LCD), a plasma display (PDP), an electroluminescence display (ELD), and protection placed on the front side (visual side) thereof. By filling the gap between the panel and the touch panel member with an adhesive, it is possible to suppress the reflection of the incident light and the emitted light from the display image at the air layer interface. As a method of filling the gaps between the image display device constituent members with an adhesive, a method of filling the gaps between the image display device constituent members with an adhesive sheet is known.
　また、車載用の画像表示装置においては、紫外線に暴露されやすいことから、画像表示装置内部の導電部材や偏光板等の樹脂部材が紫外線暴露により黄変劣化するのを防ぐため、窓部材やフロントパネル部材として、紫外線遮蔽性のガラスカバー部材や樹脂カバー部材等の構成部材が使用されることがある。
　この場合には、紫外線遮蔽性の構成部材の外側から紫外線を照射した際に、紫外線遮蔽性の構成部材を透過できる波長領域の光によって光硬化できる光硬化性粘着シートが使用されることがある。 In addition, since in-vehicle image display devices are easily exposed to ultraviolet rays, window members and fronts are used to prevent yellowing deterioration of resin members such as conductive members and polarizing plates inside the image display devices due to ultraviolet exposure. As the panel member, a constituent member such as a glass cover member or a resin cover member having an ultraviolet shielding property may be used.
In this case, a photocurable adhesive sheet that can be photocured by light in a wavelength range that can pass through the ultraviolet shielding component when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component may be used. ..
　例えば、特許文献１には、活性エネルギー線硬化性成分と、濃度０．１質量％のアセトニトリル溶液における波長３９０ｎｍ、光路長１０ｍｍの吸光度が０．３以上である光重合開始剤とを含有する無溶剤型粘着性組成物から粘着シートを製造して、この粘着シートと紫外線遮蔽性部材と貼合して積層体を作製し、その後、紫外線遮蔽性部材を通して活性エネルギー線を照射し、粘着シートを硬化させる、表示体の製造方法が開示されている。 For example, Patent Document 1 contains an active energy ray-curable component and a photopolymerization initiator having a wavelength of 390 nm and an optical path length of 10 mm in an acetonitrile solution having a concentration of 0.1% by mass and having an absorbance of 0.3 or more. A pressure-sensitive adhesive sheet is produced from the solvent-type pressure-sensitive adhesive composition, and the pressure-sensitive adhesive sheet is bonded to an ultraviolet-shielding member to prepare a laminated body. A method for producing a display body to be cured is disclosed.
　また、特許文献２には、濃度０．１質量％のアセトニトリル溶液における波長３８０ｎｍの吸光度が０．３以上である光重合開始剤を含有する紫外線硬化性の粘着シートを介して、紫外線吸収剤を含有する表示体構成部材を貼合してなる積層体を作製し、前記紫外線吸収剤を含有する表示体構成部材越しに紫外線を照射し、粘着シートを硬化させる表示体の製造方法が開示されている。 Further, Patent Document 2 describes an ultraviolet absorber via an ultraviolet curable pressure-sensitive adhesive sheet containing a photopolymerization initiator having an absorbance of 380 nm at a wavelength of 0.3 or more in an acetonitrile solution having a concentration of 0.1% by mass. Disclosed is a method for manufacturing a display body in which a laminated body formed by laminating the contained display body constituent members is produced, and ultraviolet rays are irradiated through the display body constituent members containing the ultraviolet absorber to cure the adhesive sheet. There is.
　特許文献３には、紫外線遮蔽性を有する紫外線遮蔽部材を貼合するための粘着シートであって、前記粘着シートが活性エネルギー線硬化性成分と、前記活性エネルギー線硬化性成分（Ａ）の硬化物を含有する活性エネルギー線硬化性粘着剤からなり、前記紫外線遮蔽性部材越しに、３８０～４５０ｎｍの波長領域に実質的な強度の発行を有する活性エネルギー線を、前記粘着シートに対して１０００ｍＪ／ｃｍ2の光量にて照射して硬化させたときの粘着シートのゲル分率が７０％以上、１００％未満となる粘着シートが開示されている。 Patent Document 3 describes an adhesive sheet for bonding an ultraviolet shielding member having an ultraviolet shielding property, wherein the adhesive sheet cures an active energy ray curable component and the active energy ray curable component (A). An active energy ray, which comprises an active energy ray-curable pressure-sensitive adhesive and has a substantial intensity emission in the wavelength region of 380 to 450 nm through the ultraviolet shielding member, is 1000 mJ / J / per to the pressure-sensitive adhesive sheet. A pressure-sensitive adhesive sheet having a gel content of 70% or more and less than 100% when cured by irradiating with a light amount of cm 2 is disclosed.
　特許文献４には、紫外線吸収剤を含有する表示体構成部材と、前記紫外線吸収剤を含有する表示体構成部材を貼合する硬化後粘着剤層とを備えた表示体の製造方法であって、前記表示体構成部材越しに紫外線を照射することにより、粘着剤層を硬化させて硬化後粘着剤層とし、硬化後粘着剤層のゲル分率を４０％以上とする表示体の製造方法が開示されている。 Patent Document 4 is a method for manufacturing a display body including a display body component containing an ultraviolet absorber and a cured pressure-sensitive adhesive layer for laminating the display body component containing the ultraviolet absorber. A method for manufacturing a display body is such that the pressure-sensitive adhesive layer is cured to form a cured pressure-sensitive adhesive layer by irradiating the display body constituent members with ultraviolet rays, and the gel content of the cured pressure-sensitive adhesive layer is 40% or more. It has been disclosed.
特許第６３６０６０５号公報Japanese Patent No. 6360605 特許第６４２０５１９号公報Japanese Patent No. 6420519 特許第６４３８１６５号公報Japanese Patent No. 6438165 特許第６６７６７２０号公報Japanese Patent No. 66676720
　画像表示装置部材として使用される偏光板は湿熱環境下において、偏光子を構成するポリビニルアルコール系樹脂のポリエン化による変色やヨウ素の色抜け等の変色が発生することが知られている。また、偏光板と他の構成部材とが光硬化性粘着シートを介して積層された積層体においては、偏光板と光硬化性粘着シートとの相互作用により、湿熱環境下での偏光板の変色が促進される場合がある。そのため、前記車載用の画像表示装置等においても、高温高湿環境下での優れた耐久性が要求される。 It is known that the polarizing plate used as an image display device member undergoes discoloration such as discoloration due to polyene conversion of the polyvinyl alcohol-based resin constituting the polarizing element and color loss of iodine in a moist heat environment. Further, in the laminated body in which the polarizing plate and other constituent members are laminated via the photocurable pressure-sensitive adhesive sheet, the color change of the polarizing plate in a moist heat environment due to the interaction between the polarizing plate and the photocurable pressure-sensitive adhesive sheet. May be promoted. Therefore, even in the in-vehicle image display device and the like, excellent durability in a high temperature and high humidity environment is required.
　前記特許文献１～４には、紫外線遮蔽性の構成部材の外側から紫外線を照射した際に、紫外線遮蔽性の構成部材を透過できる波長領域の光によって光硬化でき、かつ、過酷な高温高湿環境下においても発泡、剥がれ等の外観不良が見られない粘着シートが開示されており、用いる光重合開始剤としては、アシルホスフィンオキサイド系光重合開始剤のみが例示されている。しかしながら、特許文献１～４で開示されている粘着シートは、過酷な高温高湿環境下における偏光板の変色の課題について言及されていない。 In Patent Documents 1 to 4, when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component, the light can be cured by light in a wavelength range that can pass through the ultraviolet shielding component, and the temperature and humidity are severe. A pressure-sensitive adhesive sheet in which appearance defects such as foaming and peeling are not observed even in an environment is disclosed, and as the photopolymerization initiator used, only an acylphosphine oxide-based photopolymerization initiator is exemplified. However, the pressure-sensitive adhesive sheets disclosed in Patent Documents 1 to 4 do not mention the problem of discoloration of the polarizing plate in a harsh high temperature and high humidity environment.
　そのため、可視光により硬化することができ、さらに、湿熱環境下での偏光板の変色を抑制できる光硬化性粘着シートとしては、満足できるものがなく、改善の余地があるものである。 Therefore, there is no satisfactory photocurable pressure-sensitive adhesive sheet that can be cured by visible light and can suppress discoloration of the polarizing plate in a moist heat environment, and there is room for improvement.
　本発明は、紫外線遮蔽性の構成部材の外側から紫外線を照射した際に、紫外線遮蔽性の構成部材を透過できる波長領域の光によって光硬化でき、かつ、過酷な高温高湿環境下においても偏光板の変色や、発泡、剥がれ等の外観不良が見られない光硬化性粘着シートと、偏光板とを備える積層体を提供する。 INDUSTRIAL APPLICABILITY The present invention can be photocured by light in a wavelength range that can pass through an ultraviolet shielding component when ultraviolet rays are irradiated from the outside of the ultraviolet shielding component, and is polarized even in a harsh high temperature and high humidity environment. Provided is a laminate comprising a photocurable pressure-sensitive adhesive sheet and a polarizing plate, in which discoloration of the plate, foaming, peeling and other appearance defects are not observed.
　本発明者は、鋭意検討した結果、光硬化性粘着シートとして、可視光によりラジカルを発生することができる光重合開始剤を用い、かつ、粘着剤層に含まれるアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤を極力少なくしたものを用いることで、上記課題を解決できることを見出した。 As a result of diligent studies, the present inventor uses a photopolymerization initiator capable of generating radicals by visible light as a photocurable pressure-sensitive adhesive sheet, and an acylphosphine oxide-based photopolymerization initiator contained in the pressure-sensitive adhesive layer. It has been found that the above-mentioned problems can be solved by using a phenylglycilate-based photopolymerization initiator as little as possible.
　すなわち、本発明は、以下の〔１〕～〔１４〕を、その要旨とする。
〔１〕　［I］偏光板／光硬化性粘着シートの層構成に積層された積層体であって、
［II］偏光板が、偏光子の両面が保護フィルムで積層された層構成を有し、
［III］光硬化性粘着シートと偏光子との距離（α）が、８０μｍ以下であり、
［IV－１］光硬化性粘着シートが、（メタ）アクリル酸エステル（共）重合体および光重合開始剤（Ａ）を含む光硬化性粘着剤組成物から形成され、かつ、
［IV－２］波長３９０ｎｍでの光線透過率が９０％未満、波長４１０ｎｍでの光線透過率が８０％以上であり、
［IV－３］前記光重合開始剤（Ａ）として前記光硬化性粘着剤組成物に含まれるアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤の合計の濃度が０．５質量％以下である、
積層体。
〔２〕　［IV－４］前記光硬化性粘着シートが、波長３９０～４１０ｎｍの光照射においても硬化できる光硬化性粘着シートである、〔１〕記載の積層体。
〔３〕　前記光硬化性粘着シートを介して、他の構成部材（Ｘ）が積層され、前記他の構成部材（Ｘ）が、波長３６５ｎｍでの光線透過率が１０％以下、かつ、波長４０５ｎｍでの光線透過率が６０％以上である、〔１〕又は〔２〕記載の積層体。
〔４〕　前記他の構成部材（Ｘ）が、紫外線遮光性カバー材である〔３〕記載の積層体。
〔５〕　前記偏光板における保護フィルムが、トリアセチルセルロース樹脂フィルムである、〔１〕～〔４〕のいずれかに記載の積層体。
〔６〕　前記光硬化性粘着シートと偏光子との距離（α）と、前記光硬化性粘着シートの厚み（β）との比（α／β）が０．１～０．５である、〔１〕～〔５〕のいずれかに記載の積層体。
〔７〕　前記光硬化性粘着シートの厚み（β）が５０～５００μｍである、〔１〕～〔６〕のいずれかに記載の積層体。
〔８〕　前記光重合開始剤（Ａ）が、α－アミノアセトフェノン系光重合開始剤および、ケトクマリン系光重合開始剤からなる群から選択される少なくとも１種の光重合開始剤を含有する、〔１〕～〔７〕のいずれかに記載の積層体。
〔９〕　前記光硬化性粘着シートのイエローインデックス値（ＹＩ値）が、２．０以下である、〔１〕～〔８〕のいずれかに記載の積層体。
〔１０〕　前記光硬化性粘着剤組成物が、３官能以上の多官能（メタ）アクリレート及び／又はシランカップリング剤を含有する、〔１〕～〔９〕のいずれかに記載の積層体。
〔１１〕　前記（メタ）アクリル酸エステル（共）重合体が、枝成分としてマクロモノマーを備えたグラフト共重合体である、〔１〕～〔１０〕のいずれかに記載の積層体。
〔１２〕　前記光硬化性粘着シートにおいて、該粘着シートに紫外線遮蔽性を有する紫外線遮蔽性部材を介して波長４０５ｎｍでの積算光量が３０００（ｍＪ／ｃｍ2）である光を照射したときに、光照射前のゲル分率Ｇ１と光照射後のゲル分率Ｇ２との差（光照射後のゲル分率Ｇ２－光照射前のゲル分率Ｇ１）が１０％以上である、〔１〕～〔１１〕のいずれかに記載の積層体。
〔１３〕　前記光硬化性粘着シートが、２層以上の複層構成である、〔１〕～〔１２〕のいずれかに記載の積層体。
〔１４〕　〔１〕～〔１３〕のいずれかに記載の積層体が、可視光により硬化された積層構造体。 That is, the gist of the present invention is the following [1] to [14].
[1] [I] A laminate laminated in a layer structure of a polarizing plate / a photocurable pressure-sensitive adhesive sheet.
[II] The polarizing plate has a layer structure in which both sides of the polarizing element are laminated with a protective film.
[III] The distance (α) between the photocurable adhesive sheet and the polarizing element is 80 μm or less.
[IV-1] The photocurable pressure-sensitive adhesive sheet is formed from a photo-curable pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer and a photopolymerization initiator (A), and
[IV-2] The light transmittance at a wavelength of 390 nm is less than 90%, and the light transmittance at a wavelength of 410 nm is 80% or more.
[IV-3] The total concentration of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition as the photopolymerization initiator (A) is 0. 5% by mass or less,
Laminated body.
[2] [IV-4] The laminate according to [1], wherein the photocurable pressure-sensitive adhesive sheet is a photo-curable pressure-sensitive adhesive sheet that can be cured even when irradiated with light having a wavelength of 390 to 410 nm.
[3] Another component (X) is laminated via the photocurable pressure-sensitive adhesive sheet, and the other component (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a wavelength of 405 nm. The laminate according to [1] or [2], wherein the light transmittance is 60% or more.
[4] The laminate according to [3], wherein the other constituent member (X) is an ultraviolet light-shielding cover material.
[5] The laminate according to any one of [1] to [4], wherein the protective film in the polarizing plate is a triacetyl cellulose resin film.
[6] The ratio (α / β) of the distance (α) between the photocurable pressure-sensitive adhesive sheet and the polarizing element to the thickness (β) of the photocurable pressure-sensitive adhesive sheet is 0.1 to 0.5. The laminate according to any one of [1] to [5].
[7] The laminate according to any one of [1] to [6], wherein the photocurable pressure-sensitive adhesive sheet has a thickness (β) of 50 to 500 μm.
[8] The photopolymerization initiator (A) contains at least one photopolymerization initiator selected from the group consisting of an α-aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator. 1] The laminate according to any one of [7].
[9] The laminate according to any one of [1] to [8], wherein the yellow index value (YI value) of the photocurable adhesive sheet is 2.0 or less.
[10] The laminate according to any one of [1] to [9], wherein the photocurable pressure-sensitive adhesive composition contains a trifunctional or higher polyfunctional (meth) acrylate and / or a silane coupling agent.
[11] The laminate according to any one of [1] to [10], wherein the (meth) acrylic acid ester (co) polymer is a graft copolymer having a macromonomer as a branch component.
[12] In the photocurable pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive sheet is irradiated with light having an integrated light amount of 3000 (mJ / cm 2 ) at a wavelength of 405 nm via an ultraviolet-shielding member having an ultraviolet-shielding property. The difference between the gel fraction G1 before light irradiation and the gel fraction G2 after light irradiation (gel fraction G2-after light irradiation 2-gel fraction G1 before light irradiation) is 10% or more, [1] to The laminate according to any one of [11].
[13] The laminate according to any one of [1] to [12], wherein the photocurable pressure-sensitive adhesive sheet has a multi-layer structure of two or more layers.
[14] The laminated structure according to any one of [1] to [13] is a laminated structure cured by visible light.
　本発明の積層体は、可視光によって硬化させることができ、過酷な高温高湿環境下においても偏光板が変色せず、さらに、発泡や剥がれ等の外観不良を抑制することができる。 The laminate of the present invention can be cured by visible light, the polarizing plate does not discolor even in a harsh high temperature and high humidity environment, and appearance defects such as foaming and peeling can be suppressed.
　以下、本発明を実施するための形態について具体的に説明するが、本発明はこれらに限定されるものではない。
　本発明において、「（メタ）アクリル」とはアクリルあるいはメタクリルを、「（メタ）アクリロイル」とはアクリロイルあるいはメタクリロイルを、「（メタ）アクリレート」とはアクリレートあるいはメタクリレートをそれぞれ意味するものである。
　また、「（メタ）アクリル酸エステル（共）重合体」とは、少なくとも１種の（メタ）アクリレート系モノマーを含む重合成分を重合して得られる樹脂であり、「（共）重合体」とは、重合体および共重合体を包括する意味である。
　本発明において、「シート」とは、特に「フィルム」、「テープ」と区別するものではなく、これらも含めた意味として記載するものである。
　なお、本発明において「Ｘ～Ｙ」（Ｘ，Ｙは任意の数字）と表現する場合、特にことわらない限り「Ｘ以上Ｙ以下」の意と共に、「好ましくはＸより大きい」または「好ましくはＹより小さい」の意も包含する。
　また、「Ｘ以上」（Ｘは任意の数字）または「Ｙ以下」（Ｙは任意の数字）と表現した場合、「Ｘより大きいことが好ましい」または「Ｙ未満であることが好ましい」旨の意図も包含する。
　更に、「Ｘ及び／又はＹ（Ｘ，Ｙは任意の構成）」とは、Ｘ及びＹの少なくとも一方を意味するものであって、Ｘのみ、Ｙのみ、Ｘ及びＹ、の３通りを意味するものである。 Hereinafter, embodiments for carrying out the present invention will be specifically described, but the present invention is not limited thereto.
In the present invention, "(meth) acrylic" means acrylic or methacrylic, "(meth) acryloyl" means acryloyl or methacrylic acid, and "(meth) acrylate" means acrylate or methacrylate.
Further, the "(meth) acrylic acid ester (co) polymer" is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate-based monomer, and is referred to as a "(co) polymer". Means to include polymers and copolymers.
In the present invention, the term "sheet" is not particularly distinguished from "film" and "tape", but is described as a meaning including these.
In the present invention, when expressed as "X to Y" (X and Y are arbitrary numbers), it means "X or more and Y or less" and "preferably larger than X" or "preferably larger than X". It also includes the meaning of "smaller than Y".
Further, when expressed as "X or more" (X is an arbitrary number) or "Y or less" (Y is an arbitrary number), it means "preferably larger than X" or "preferably less than Y". Intention is also included.
Further, "X and / or Y (X and Y are arbitrary configurations)" means at least one of X and Y, and means three types of X only, Y only, and X and Y. Is what you do.
　本発明の積層体（以下、「本積層体」と称する場合がある）は、光硬化性粘着シート／偏光板の層構成に積層された積層体である。そして、前記光硬化性粘着シートを介して、他の構成部材（Ｘ）が積層された積層体は、主に車載用の画像表示装置に用いられる。
　通常、光硬化性粘着シートは、被着体に貼合した後、紫外線照射により硬化を行い、被着体と貼り合わせる。しかし、上述のとおり、車載用の画像表示装置においては、偏光板等が紫外線により劣化しやすいことから、紫外線を遮蔽するガラスカバー部材や樹脂カバー部材が用いられることがある。したがって、主として車載用の画像表示装置に用いられる、本積層体を構成する光硬化性粘着シートは、紫外線ではなく可視光により硬化できる可視光硬化性を有するものである。 The laminate of the present invention (hereinafter, may be referred to as “the present laminate”) is a laminate laminated in a layer structure of a photocurable pressure-sensitive adhesive sheet / polarizing plate. The laminated body in which the other constituent members (X) are laminated via the photocurable adhesive sheet is mainly used for an in-vehicle image display device.
Usually, the photocurable adhesive sheet is attached to the adherend, then cured by irradiation with ultraviolet rays, and then attached to the adherend. However, as described above, in an in-vehicle image display device, a glass cover member or a resin cover member that shields ultraviolet rays may be used because the polarizing plate or the like is easily deteriorated by ultraviolet rays. Therefore, the photocurable pressure-sensitive adhesive sheet constituting the present laminate, which is mainly used for an in-vehicle image display device, has visible light curability that can be cured by visible light instead of ultraviolet light.
　前記光硬化性粘着シートは、（メタ）アクリル酸エステル（共）重合体および可視光によりラジカルを発生する光重合開始剤（Ａ）を含む光硬化性粘着剤組成物から形成されるものであり、光重合開始剤（Ａ）として前記光硬化性粘着剤組成物に含まれるアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤が少ないことを特徴とする。以下光硬化性粘着剤組成物に含まれる各成分について説明する。 The photocurable pressure-sensitive adhesive sheet is formed from a photo-curable pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer and a photopolymerization initiator (A) that generates a radical by visible light. As the photopolymerization initiator (A), the amount of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition is small. Hereinafter, each component contained in the photocurable pressure-sensitive adhesive composition will be described.
〔（メタ）アクリル酸エステル（共）重合体〕
　前記光硬化性粘着剤組成物に用いる（メタ）アクリル酸エステル（共）重合体としては、例えば、アルキル（メタ）アクリレートの単独重合体の他、これと共重合可能なモノマー成分を共重合することにより得られる共重合体を挙げることができる。なかでも、（メタ）アクリル酸エステル共重合体が好ましい。 [(Meta) acrylic acid ester (co) polymer]
As the (meth) acrylic acid ester (co) polymer used in the photocurable pressure-sensitive adhesive composition, for example, in addition to the homopolymer of alkyl (meth) acrylate, a monomer component copolymerizable therewith is copolymerized. The copolymer obtained by this can be mentioned. Of these, the (meth) acrylic acid ester copolymer is preferable.
　前記（メタ）アクリル酸エステル共重合体としては、例えば、アルキル基の炭素数が１～１８のアルキル（メタ）アクリレートと、これと共重合可能なモノマー成分、例えば、（ａ）カルボキシ基含有モノマー、（ｂ）水酸基含有モノマー、（ｃ）アミノ基含有モノマー、（ｄ）エポキシ基含有モノマー、（ｅ）アミド基含有モノマー、（ｆ）ビニルモノマー、および（ｇ）マクロモノマーから選択されるいずれか一つ以上のモノマーを含むモノマー成分との共重合体を挙げることができる。なかでも、アルキル基の炭素数が１～１８のアルキル（メタ）アクリレートと、（ｅ）アミド基含有モノマー、（ｇ）マクロモノマーを含む共重合成分から得られる（メタ）アクリル酸エステル共重合体が好ましい。 Examples of the (meth) acrylic acid ester copolymer include an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms and a monomer component capable of copolymerizing with the alkyl (meth) acrylate, for example, (a) a carboxy group-containing monomer. , (B) hydroxyl group-containing monomer, (c) amino group-containing monomer, (d) epoxy group-containing monomer, (e) amide group-containing monomer, (f) vinyl monomer, and (g) macromonomer. Examples thereof include a copolymer with a monomer component containing one or more monomers. Among them, a (meth) acrylic acid ester copolymer obtained from a copolymer component containing an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, (e) an amide group-containing monomer, and (g) a macromonomer. Is preferable.
［アルキル基の炭素数が１～１８のアルキル（メタ）アクリレート］
　前記アルキル基の炭素数が１～１８のアルキル（メタ）アクリレートとしては、例えば、メチル（メタ）アクリレート、エチル（メタ）アクリレート、ｎ－プロピル（メタ）アクリレート、ｎ－ブチル（メタ）アクリレート、ペンチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、ヘプチル（メタ）アクリレート、ｎ－オクチル（メタ）アクリート、ノニル（メタ）アクリレート、デシル（メタ）アクリレート、ウンデシル（メタ）アクリレート、ラウリル（メタ）アクリレート、トリデシル（メタ）アクリレート、テトラデシル（メタ）アクリレート、セチル（メタ）アクリレート、ステアリル（メタ）アクリレート等の直鎖アルキル（メタ）アクリレート；イソプロピル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｓｅｃ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、イソペンチル（メタ）アクリレート、ネオペンチル（メタ）アクリレート、２－エチルヘキシル（メタ）アクリレート、イソオクチル（メタ）アクリレート、イソノニル（メタ）アクリレート、ｔ－ブチルシクロヘキシル（メタ）アクリレート、イソデシル（メタ）アクリレート、イソステアリル（メタ）アクリレート等の分岐アルキル（メタ）アクリレート；シクロヘキシル（メタ）アクリレート、イソボルニル（メタ）アクリレート、３，５，５－トリメチルシクロヘキサン（メタ）アクリレート、ジシクロペンタニル（メタ）アクリレート、ジシクロペンテニル（メタ）アクリレート、ジシクロペンテニルオキシエチル（メタ）アクリレート等の脂環式アルキル（メタ）アクリレート等が挙げられる。これらは単独でもしくは２種以上を併せて用いてもよい。なかでも、アルキル基の炭素数が６～１４の直鎖、分岐アルキル（メタ）アクリレートが好ましく、より好ましくはラウリル（メタ）アクリレート、２－エチルへキシル（メタ）アクリレートである。 [Alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group]
Examples of the alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, n-butyl (meth) acrylate, and pentyl. (Meta) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, n-octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate, lauryl (meth) acrylate, tridecyl Linear alkyl (meth) acrylates such as (meth) acrylate, tetradecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate; isopropyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl (meth) Acrylate, t-butyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate , Isodecyl (meth) acrylate, branched alkyl (meth) acrylate such as isostearyl (meth) acrylate; cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 3,5,5-trimethylcyclohexane (meth) acrylate, dicyclopenta. Examples thereof include alicyclic alkyl (meth) acrylates such as nyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and dicyclopentenyloxyethyl (meth) acrylate. These may be used alone or in combination of two or more. Of these, linear and branched alkyl (meth) acrylates having an alkyl group having 6 to 14 carbon atoms are preferable, and lauryl (meth) acrylate and 2-ethylhexyl (meth) acrylate are more preferable.
　前記アルキル基の炭素数が１～１８のアルキル（メタ）アクリレートの含有量は、共重合体の全モノマー成分中に、通常３０～９０質量％であり、好ましくは３５～８８質量％、より好ましくは４０～８５質量％、特に好ましくは５５～８５質量％である。かかる含有量が少なすぎると疎水性が下がり吸水を抑制しづらくなる傾向があり、多すぎると極性が下がり粘着力が低下する傾向がある。 The content of the alkyl (meth) acrylate having 1 to 18 carbon atoms in the alkyl group is usually 30 to 90% by mass, preferably 35 to 88% by mass, more preferably 35 to 88% by mass in all the monomer components of the copolymer. Is 40 to 85% by mass, particularly preferably 55 to 85% by mass. If the content is too small, the hydrophobicity tends to decrease and it tends to be difficult to suppress water absorption, and if it is too large, the polarity tends to decrease and the adhesive strength tends to decrease.
［（ａ）カルボキシ基含有モノマー］
　前記（ａ）カルボキシ基含有モノマーとしては、例えば、（メタ）アクリル酸、２－（メタ）アクリロイルオキシエチルヘキサヒドロフタル酸、２－（メタ）アクリロイルオキシプロピルヘキサヒドロフタル酸、２－（メタ）アクリロイルオキシエチルフタル酸、２－（メタ）アクリロイルオキシプロピルフタル酸、２－（メタ）アクリロイルオキシエチルマレイン酸、２－（メタ）アクリロイルオキシプロピルマレイン酸、２－（メタ）アクリロイルオキシエチルコハク酸、２－（メタ）アクリロイルオキシプロピルコハク酸、クロトン酸、フマル酸、マレイン酸、イタコン酸等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 [(A) Monomer containing carboxy group]
Examples of the (a) carboxy group-containing monomer include (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyloxypropyl hexahydrophthalic acid, and 2- (meth). Acryloyloxyethyl phthalic acid, 2- (meth) acryloyloxypropyl phthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropyl maleic acid, 2- (meth) acryloyloxyethyl succinic acid, 2- (Meta) acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid and the like can be mentioned. These may be used alone or in combination of two or more.
　前記（ａ）カルボキシ基含有モノマーの含有量は、共重合体の全モノマー成分中に通常１０質量％以下、好ましくは８質量％以下、特に好ましくは５質量％以下である。 The content of the (a) carboxy group-containing monomer is usually 10% by mass or less, preferably 8% by mass or less, and particularly preferably 5% by mass or less in all the monomer components of the copolymer.
［（ｂ）水酸基含有モノマー］
　前記（ｂ）水酸基含有モノマーとしては、例えば、２－ヒドロキシエチル（メタ）アクリレート、２－ヒドロキシプロピル（メタ）アクリレート、３－ヒドロキシプロピル（メタ）アクリレート、２－ヒドロキシブチル（メタ）アクリレート等のヒドロキシアルキル（メタ）アクリレート等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 [(B) Hydroxyl group-containing monomer]
Examples of the (b) hydroxyl group-containing monomer include hydroxy such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, and 2-hydroxybutyl (meth) acrylate. Alkyl (meth) acrylate and the like can be mentioned. These may be used alone or in combination of two or more.
　前記（ｂ）水酸基含有モノマーの含有量は、共重合体の全モノマー成分中に、通常３０質量％以下、好ましくは２５質量％以下、特に好ましくは２０質量％以下である。 The content of the hydroxyl group-containing monomer (b) is usually 30% by mass or less, preferably 25% by mass or less, and particularly preferably 20% by mass or less in all the monomer components of the copolymer.
［（ｃ）アミノ基含有モノマー］
　前記（ｃ）アミノ基含有モノマーとしては、例えば、アミノメチル（メタ）アクリレート、アミノエチル（メタ）アクリレート、アミノプロピル（メタ）アクリレート、アミノイソプロピル（メタ）アクリレート等のアミノアルキル（メタ）アクリレート、Ｎ－アルキルアミノアルキル（メタ）アクリレート、Ｎ，Ｎ－ジメチルアミノエチル（メタ）アクリレート、Ｎ，Ｎ－ジメチルアミノプロピル（メタ）アクリレート等のＮ，Ｎ－ジアルキルアミノアルキル（メタ）アクリレート等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 [(C) Amino group-containing monomer]
Examples of the (c) amino group-containing monomer include aminoalkyl (meth) acrylates such as aminomethyl (meth) acrylate, aminoethyl (meth) acrylate, aminopropyl (meth) acrylate, and aminoisopropyl (meth) acrylate, and N. -N, N-dialkylaminoalkyl (meth) acrylates such as alkylaminoalkyl (meth) acrylates, N, N-dimethylaminoethyl (meth) acrylates, N, N-dimethylaminopropyl (meth) acrylates and the like can be mentioned. can. These may be used alone or in combination of two or more.
　前記（ｃ）アミノ基含有モノマーの含有量は、共重合体の全モノマー成分中に、通常２０質量％以下、好ましくは１０質量％以下、特に好ましくは１０質量％以下である。 The content of the (c) amino group-containing monomer is usually 20% by mass or less, preferably 10% by mass or less, and particularly preferably 10% by mass or less in all the monomer components of the copolymer.
［（ｄ）エポキシ基含有モノマー］
　前記（ｄ）エポキシ基含有モノマーとしては、例えば、グリシジル（メタ）アクリレート、メチルグリシジル（メタ）アクリレート、３，４－エポキシシクロヘキシルメチル（メタ）アクリレート、４－ヒドロキシブチル（メタ）アクリレートグリシジルエーテル等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 [(D) Epoxy group-containing monomer]
Examples of the (d) epoxy group-containing monomer include glycidyl (meth) acrylate, methyl glycidyl (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, and 4-hydroxybutyl (meth) acrylate glycidyl ether. Can be mentioned. These may be used alone or in combination of two or more.
　前記（ｄ）エポキシ基含有モノマーの含有量は、共重合体の全モノマー成分中に、通常２０質量％以下、好ましくは１０質量％以下である。 The content of the epoxy group-containing monomer (d) is usually 20% by mass or less, preferably 10% by mass or less in all the monomer components of the copolymer.
［（ｅ）アミド基含有モノマー］
　前記（ｅ）アミド基含有モノマーとしては、例えば、（メタ）アクリルアミド、Ｎ，Ｎ－ジメチル（メタ）アクリルアミド、Ｎ－ブチル（メタ）アクリルアミド、Ｎ－メチロール（メタ）アクリルアミド、Ｎ－メチロールプロパン（メタ）アクリルアミド、Ｎ－メトキシメチル（メタ）アクリルアミド、Ｎ－ブトキシメチル（メタ）アクリルアミド、ダイアセトン（メタ）アクリルアミド、マレイン酸アミド、マレイミド等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。なかでも、（メタ）アクリルアミドが好ましい。 [(E) Amide group-containing monomer]
Examples of the (e) amide group-containing monomer include (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N-butyl (meth) acrylamide, N-methylol (meth) acrylamide, and N-methylolpropane (meth). ) Acrylamide, N-methoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, diacetone (meth) acrylamide, maleic acid amide, maleimide and the like can be mentioned. These may be used alone or in combination of two or more. Of these, (meth) acrylamide is preferable.
　前記（ｅ）アミド基含有モノマーの含有量は、共重合体の全モノマー成分中に、通常１～２０質量％、なかでも優れた粘着物性を得る観点から好ましくは１．５～１５質量％、特に好ましくは２～１０質量％である。 The content of the (e) amide group-containing monomer is usually 1 to 20% by mass, preferably 1.5 to 15% by mass from the viewpoint of obtaining excellent adhesive properties, in all the monomer components of the copolymer. Particularly preferably, it is 2 to 10% by mass.
［（ｆ）ビニルモノマー］
　前記（ｆ）ビニルモノマーとしては、ビニル基を分子内に有する化合物を挙げることができる。このような化合物としては、例えば、酢酸ビニル、プロピオン酸ビニル、ラウリン酸ビニル等のビニルエステルモノマー、スチレン、クロロスチレン、クロロメチルスチレン、α－メチルスチレンや、その他の置換スチレン等の芳香族ビニルモノマー、ポリアルキレングリコールジ（メタ）アクリレート類等が挙げられる。これらは１種または２種以上を組み合わせてもよい。 [(F) Vinyl monomer]
Examples of the (f) vinyl monomer include compounds having a vinyl group in the molecule. Examples of such compounds include vinyl ester monomers such as vinyl acetate, vinyl propionate and vinyl laurate, aromatic vinyl monomers such as styrene, chlorostyrene, chloromethylstyrene, α-methylstyrene and other substituted styrenes. , Polyalkylene glycol di (meth) acrylates and the like. These may be one kind or a combination of two or more kinds.
　前記（ｆ）ビニルモノマーの含有量は、共重合体の全モノマー成分中に、通常４０質量％以下、好ましくは３５質量％以下、特に好ましくは３０質量％以下である。 The content of the vinyl monomer (f) is usually 40% by mass or less, preferably 35% by mass or less, and particularly preferably 30% by mass or less in all the monomer components of the copolymer.
［（ｇ）マクロモノマー］
　前記（ｇ）マクロモノマーとは、末端の官能基と高分子量骨格成分とを有する高分子単量体である。なかでも、前記（ｇ）マクロモノマーとしては、共重合により（メタ）アクリル酸エステル共重合体となった際に、側鎖の炭素数が２０以上となるモノマーであることが好ましい。 [(G) Macromonomer]
The (g) macromonomer is a polymer monomer having a terminal functional group and a high molecular weight skeleton component. Among them, the (g) macromonomer is preferably a monomer having 20 or more carbon atoms in the side chain when it becomes a (meth) acrylic acid ester copolymer by copolymerization.
　前記（ｇ）マクロモノマーを用いることにより、（メタ）アクリル酸エステル共重合体の枝成分としてマクロモノマーが導入され、（メタ）アクリル酸エステル共重合体をグラフト共重合体とすることができる。また、（ｇ）マクロモノマーと、それ以外のモノマーの選択や配合比率によって、グラフト共重合体の主鎖と側鎖の特性を変化させることができる。 By using the (g) macromonomer, the macromonomer is introduced as a branch component of the (meth) acrylic acid ester copolymer, and the (meth) acrylic acid ester copolymer can be used as a graft copolymer. Further, the characteristics of the main chain and the side chain of the graft copolymer can be changed by selecting (g) the macromonomer and other monomers and the blending ratio.
　（ｇ）マクロモノマーが有する末端官能基としては、例えば、（メタ）アクリロイル基、ビニル基等のラジカル性重合基、ヒドロキシ基、イソシアネート基、エポキシ基、カルボキシ基、アミノ基、アミド基、チオール基等の官能基を挙げることができる。なかでも、他のモノマーと共重合可能なラジカル重合性基を有するものが好ましく、（メタ）アクリロイル基が特に好ましい。前記末端官能基は一つあるいは二つ以上含有していてもよく、なかでも一つであるものが特に好ましい。
　また、（ｇ）マクロモノマーは、末端官能基以外にも前記で挙げられる官能基を有していてもよい。 Examples of the terminal functional group of the (g) macromonomer include a radical polymerization group such as a (meth) acryloyl group and a vinyl group, a hydroxy group, an isocyanate group, an epoxy group, a carboxy group, an amino group, an amide group and a thiol group. And other functional groups can be mentioned. Among them, those having a radically polymerizable group copolymerizable with other monomers are preferable, and (meth) acryloyl group is particularly preferable. The terminal functional group may be contained at one or two or more, and one of them is particularly preferable.
Further, the (g) macromonomer may have a functional group mentioned above in addition to the terminal functional group.
　前記（ｇ）マクロモノマーの骨格成分は、（メタ）アクリル酸エステル（共）重合体又はビニル系重合体から構成されるのが好ましく、例えば、前記アルキル基の炭素数が１～１８のアルキル（メタ）アクリレート、前記（ａ）カルボキシ基含有モノマー、前記（ｂ）水酸基含有モノマー、前記（ｄ）エポキシ基含有モノマー、前記（ｅ）アミド基含有モノマーで例示したものが挙げられる。これらは単独でもしくは２種以上を併せて用いてもよい。なかでも、（ｇ）マクロモノマーの骨格成分は、疎水性のモノマーと、親水性のモノマーとを構成単位として含有するのが好ましい。 The skeleton component of the (g) macromonomer is preferably composed of a (meth) acrylic acid ester (co) polymer or a vinyl-based polymer, for example, an alkyl having 1 to 18 carbon atoms in the alkyl group. Examples thereof include a meta) acrylate, the (a) carboxy group-containing monomer, the (b) hydroxyl group-containing monomer, the (d) epoxy group-containing monomer, and the (e) amide group-containing monomer. These may be used alone or in combination of two or more. Among them, the skeleton component of (g) macromonomer preferably contains a hydrophobic monomer and a hydrophilic monomer as constituent units.
　前記の疎水性のモノマーとしては、極性基を有さないアルキルエステル（但し、メチル（メタ）アクリレートを除く）が好ましく、例えば、ｎ－ブチル（メタ）アクリレート、イソブチル（メタ）アクリレート、ｓｅｃ－ブチル（メタ）アクリレート、ｔ－ブチル（メタ）アクリレート、ペンチル（メタ）アクリレート、イソペンチル（メタ）アクリレート、ネオペンチル（メタ）アクリレート、ヘキシル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、ヘプチル（メタ）アクリレート、２－エチルヘキシルアクリレート、ｎ－オクチルアクリート、イソオクチルアクリレート、ノニル（メタ）アクリレート、イソノニル（メタ）アクリレート、ｔ－ブチルシクロヘキシル（メタ）アクリレート、デシル（メタ）アクリレート、イソデシル（メタ）アクリレート、ウンデシル（メタ）アクリレート、ラウリル（メタ）アクリレート、セチル（メタ）アクリレート、ステアリル（メタ）アクリレート、イソステアリル（メタ）アクリレート、ベヘニル（メタ）アクリレート、イソボルニル（メタ）アクリレート、シクロヘキシル（メタ）アクリレート、ジシクロペンテニルオキシエチル（メタ）アクリレ－ト、メチルメタクリレート等の（メタ）アクリレートが挙げられる。これらは単独でもしくは２種以上を併せて用いてもよい。 As the hydrophobic monomer, an alkyl ester having no polar group (excluding methyl (meth) acrylate) is preferable, and for example, n-butyl (meth) acrylate, isobutyl (meth) acrylate, sec-butyl. (Meta) acrylate, t-butyl (meth) acrylate, pentyl (meth) acrylate, isopentyl (meth) acrylate, neopentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, heptyl (meth) acrylate, 2 -Ethylhexyl acrylate, n-octyl acrylate, isooctyl acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, undecyl (meth) Acrylate, lauryl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, behenyl (meth) acrylate, isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentenyloxyethyl Examples thereof include (meth) acrylates such as (meth) acrylicate and methyl methacrylate. These may be used alone or in combination of two or more.
　また、前記アルキルエステル以外の疎水性のモノマーとしては、例えば、酢酸ビニル、スチレン、ｔ－ブチルスチレン、α－メチルスチレン、ビニルトルエン、アルキルビニルモノマー等のビニルモノマー等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 Examples of hydrophobic monomers other than the alkyl ester include vinyl monomers such as vinyl acetate, styrene, t-butyl styrene, α-methyl styrene, vinyl toluene, and alkyl vinyl monomers. These may be used alone or in combination of two or more.
　前記の親水性のモノマーとしては、メチル（メタ）アクリレートや極性基を有するエステルが好ましく、例えば、メチル（メタ）アクリレートや、テトラヒドロフルフリル（メタ）アクリレート、ヒドロキシエチル（メタ）アクリレート、ヒドロキシプロピル（メタ）アクリレート、ヒドロキシブチル（メタ）アクリレート、グリセロール（メタ）アクリレート等の水酸基含有（メタ）アクリレート、（メタ）アクリル酸、２－（メタ）アクリロイルオキシエチルヘキサヒドロフタル酸、２－（メタ）アクリロイルオキシプロピルヘキサヒドロフタル酸、２－（メタ）アクリロイルオキシエチルフタル酸、２－（メタ）アクリロイルオキシプロピルフタル酸、２－（メタ）アクリロイルオキシエチルマレイン酸、２－（メタ）アクリロイルオキシプロピルマレイン酸、２－（メタ）アクリロイルオキシエチルコハク酸、２－（メタ）アクリロイルオキシプロピルコハク酸、クロトン酸、フマル酸、マレイン酸、イタコン酸、マレイン酸モノメチル、イタコン酸モノメチル等のカルボキシ基含有モノマー、無水マレイン酸、無水イタコン酸等の酸無水物基含有モノマー、（メタ）アクリル酸グリシジル、α－エチルアクリル酸グリシジル、（メタ）アクリル酸３,４－エポキシブチル等のエポキシ基含有モノマー、メトキシポリエチレングリコール（メタ）アクリレート等のアルコキシポリアルキレングリコール（メタ）アクリレート、Ｎ，Ｎ－ジメチルアクリルアミド、ヒドロキシエチルアクリルアミド等を挙げることができる。これらは単独でもしくは２種以上を併せて用いてもよい。 As the hydrophilic monomer, methyl (meth) acrylate and an ester having a polar group are preferable, and for example, methyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, hydroxyethyl (meth) acrylate, and hydroxypropyl (meth) ( Hydroxyl-containing (meth) acrylates such as meta) acrylates, hydroxybutyl (meth) acrylates and glycerol (meth) acrylates, (meth) acrylic acid, 2- (meth) acryloyloxyethyl hexahydrophthalic acid, 2- (meth) acryloyl Oxypropylhexahydrophthalic acid, 2- (meth) acryloyloxyethylphthalic acid, 2- (meth) acryloyloxypropylphthalic acid, 2- (meth) acryloyloxyethyl maleic acid, 2- (meth) acryloyloxypropylmaleic acid , 2- (meth) acryloyloxyethyl succinic acid, 2- (meth) acryloyloxypropyl succinic acid, crotonic acid, fumaric acid, maleic acid, itaconic acid, monomethyl maleate, monomethyl itaconate and other carboxy group-containing monomers, anhydrous Acid anhydride group-containing monomers such as maleic acid and itaconic acid anhydride, epoxy group-containing monomers such as (meth) glycidyl acrylate, α-ethyl acrylate glycidyl, and (meth) acrylate butyl 3,4-epoxybutyl, methoxypolyethylene glycol. Examples thereof include alkoxypolyalkylene glycol (meth) acrylate such as (meth) acrylate, N, N-dimethylacrylamide, hydroxyethylacrylamide and the like. These may be used alone or in combination of two or more.
　前記（ｇ）マクロモノマーにおいては、なかでも、グラフト共重合体の主鎖と側鎖のマクロモノマーが適度な相分離構造となる観点から、疎水性のモノマーとしてイソボニル（メタ）アクリレート、親水性のモノマーとしてメチル（メタ）アクリレートを１：１で反応させたマクロモノマーが好ましい。 Among the macromonomers (g), isobonyl (meth) acrylate and hydrophilic are used as hydrophobic monomers from the viewpoint that the macromonomers of the main chain and the side chains of the graft copolymer have an appropriate phase separation structure. As the monomer, a macromonomer obtained by reacting methyl (meth) acrylate in a ratio of 1: 1 is preferable.
　また、前記（ｇ）マクロモノマーのガラス転移温度（Ｔｇ）は、前記（メタ）アクリル酸エステル（共）重合体を構成する共重合成分のガラス転移温度よりも高いことが好ましい。
　具体的には、（ｇ）マクロモノマーのガラス転移温度（Ｔｇ）は、光硬化性粘着剤組成物の加熱溶融温度（ホットメルト温度）に影響するため、３０～１２０℃であるのが好ましく、より好ましくは４０～１１０℃、特に好ましくは５０～１００℃である。（ｇ）マクロモノマーのガラス転移温度（Ｔｇ）が前記範囲内であれば、分子量を調整することにより、優れた加工性や保管安定性を保持できるとともに、５０～８０℃付近でホットメルト性を有するようにできる傾向がある。
　前記（ｇ）マクロモノマーのガラス転移温度とは、当該マクロモノマー自体のガラス転移温度を意味し、示差走査熱量計（ＤＳＣ）で測定することができる。 Further, the glass transition temperature (Tg) of the (g) macromonomer is preferably higher than the glass transition temperature of the copolymerization component constituting the (meth) acrylic acid ester (co) polymer.
Specifically, the glass transition temperature (Tg) of the (g) macromonomer affects the heating and melting temperature (hot melt temperature) of the photocurable pressure-sensitive adhesive composition, and thus is preferably 30 to 120 ° C. It is more preferably 40 to 110 ° C, and particularly preferably 50 to 100 ° C. (G) When the glass transition temperature (Tg) of the macromonomer is within the above range, excellent processability and storage stability can be maintained by adjusting the molecular weight, and hot melt property can be obtained at around 50 to 80 ° C. Tend to have.
The glass transition temperature of the (g) macromonomer means the glass transition temperature of the macromonomer itself, and can be measured by a differential scanning calorimeter (DSC).
　（メタ）アクリル酸エステル（共）重合体の共重合成分として（ｇ）マクロモノマーを用いると、得られる（メタ）アクリル酸エステル（共）重合体は、室温（２５℃）状態では、枝成分同士が引き寄せ合って物理的架橋をしたような状態を維持することができる。しかも、適度な温度に加熱することで前記物理的架橋が解れて流動性を得ることができる。したがって、後述する粘着シートを形成する際に、未硬化のままで、シート形状を保持させることができる。このような物性を得るためには、マクロモノマーの分子量や含有量を調整することも好ましい。 When the (g) macromonomer is used as the copolymerization component of the (meth) acrylic acid ester (co) polymer, the obtained (meth) acrylic acid ester (co) polymer has a branch component at room temperature (25 ° C.). It is possible to maintain a state in which they are attracted to each other and physically cross-linked. Moreover, by heating to an appropriate temperature, the physical cross-linking can be dissolved and fluidity can be obtained. Therefore, when the adhesive sheet described later is formed, the sheet shape can be maintained without being cured. In order to obtain such physical properties, it is also preferable to adjust the molecular weight and content of the macromonomer.
　前記（ｇ）マクロモノマーの数平均分子量は、５００～２００００であるのが好ましく、より好ましくは６００～１００００であり、さらに好ましくは８００～８０００、特に好ましくは１０００～７０００、殊に好ましくは１５００～６０００である。 The number average molecular weight of the (g) macromonomer is preferably 500 to 20000, more preferably 600 to 10000, still more preferably 800 to 8000, particularly preferably 1000 to 7000, and particularly preferably 1500 to. It is 6000.
　また、（ｇ）マクロモノマーの含有量は、共重合体の全モノマー成分中、５～３０質量％であることが好ましく、より好ましくは６～２５質量％、特に好ましくは８～２０質量％である。かかる含有量が少なすぎると枝成分同士の物理的架橋が弱すぎて室温（２５℃）状態に置いて保管安定性が悪くなる傾向があり、多すぎると枝成分同士の物理的架橋が強すぎて加熱した時の流動性が悪くなる傾向がある。 The content of (g) macromonomer is preferably 5 to 30% by mass, more preferably 6 to 25% by mass, and particularly preferably 8 to 20% by mass in the total monomer components of the copolymer. be. If the content is too small, the physical cross-linking between the branch components tends to be too weak and the storage stability tends to deteriorate when placed at room temperature (25 ° C.), and if it is too high, the physical cross-linking between the branch components tends to be too strong. There is a tendency for the fluidity to deteriorate when heated.
　前記（メタ）アクリル酸エステル系（共）重合体は、アルキル（メタ）アクリレート又はアルキル基の炭素数が１～１８のアルキル（メタ）アクリレートと、これと共重合可能なモノマー成分とを、例えば、溶液ラジカル重合、懸濁重合、塊状重合、乳化重合等の従来公知の方法に従って重合することで得ることができる。 The (meth) acrylic acid ester-based (co) polymer is an alkyl (meth) acrylate or an alkyl (meth) acrylate having an alkyl group having 1 to 18 carbon atoms, and a monomer component copolymerizable therewith, for example. It can be obtained by polymerizing according to conventionally known methods such as solution radical polymerization, suspension polymerization, bulk polymerization, and emulsification polymerization.
　このように得られる（メタ）アクリル酸エステル系（共）重合体の重量平均分子量は、通常５万～１５０万、好ましくは７万～１３０万、特に好ましくは１０万～１２０万、更に好ましくは１５万～１００万である。 The weight average molecular weight of the (meth) acrylic acid ester-based (co) polymer thus obtained is usually 50,000 to 1,500,000, preferably 70,000 to 1,300,000, particularly preferably 100,000 to 1,200,000, and even more preferably. It is 150,000 to 1 million.
　ここで、重量平均分子量は以下の方法によって、測定される。
　（メタ）アクリル酸エステル系（共）重合体をテトラヒドロフラン（ＴＨＦ）に溶解させたものを測定試料とし、ゲル浸透クロマトグラフィー（Ｇｅｌ　Ｐｅｒｍｅａｔｉｏｎ　Ｃｈｒｏｍａｔｏｇｒａｐｈｙ：ＧＰＣ）分析装置（装置名：東ソー社製ＨＬＣ－８３２０ＧＰＣ）を用いて、下記の条件で分子量分布曲線を測定し、重量平均分子量（Ｍｗ）を求める。
　・ガードカラム：ＴＳＫｇｕａｒｄｃｏｌｕｍｎＨＸＬ
　・分離カラム：ＴＳＫｇｅｌＧＭＨＸＬ（４本）
　・温度：４０℃
　・注入量：１００μＬ
　・ポリスチレン換算
　・溶媒：ＴＨＦ
　・流速：１．０ｍＬ／ｍｉｎ Here, the weight average molecular weight is measured by the following method.
A gel permeation chromatography (GPC) analyzer (device name: HLC-8320GPC manufactured by Toso Co., Ltd.) was used as a measurement sample in which a (meth) acrylic acid ester-based (co) polymer was dissolved in tetrahydrofuran (THF). ) Is used to measure the molecular weight distribution curve under the following conditions, and the weight average molecular weight (Mw) is obtained.
-Guard column: TSKguardcolumnHXL
-Separation column: TSKgelGMHXL (4)
・ Temperature: 40 ℃
・ Injection amount: 100 μL
・ Polystyrene conversion ・ Solvent: THF
・ Flow velocity: 1.0 mL / min
　また、前記（メタ）アクリル酸エステル（共）重合体は、活性エネルギー線架橋性構造部位を有することも好ましい。
　前記活性エネルギー線架橋性構造とは、例えば、後述する光重合開始剤（Ａ）の存在下において、（メタ）アクリル酸エステル（共）重合体の一部分、または、（メタ）アクリル酸エステル（共）重合体以外の硬化成分と反応し、架橋構造を形成し得る構造部位である。 It is also preferable that the (meth) acrylic acid ester (co) polymer has an active energy ray crosslinkable structural site.
The active energy ray-crosslinkable structure is, for example, a part of a (meth) acrylic acid ester (co) polymer or a (meth) acrylic acid ester (co) in the presence of a photopolymerization initiator (A) described later. ) It is a structural part that can react with a curing component other than the polymer to form a crosslinked structure.
　前記活性エネルギー線架橋性構造部位としては、例えば（メタ）アクリロイル基、ビニル基等の不飽和二重結合を有する官能基等の炭素－炭素二重結合を有するラジカル重合性官能基を有する構造を挙げることができる。
　前記（メタ）アクリル酸エステル（共）重合体のポリマー鎖がラジカル重合性官能基を有することにより、架橋剤を含有しない場合であっても、ポリマー鎖同士が直接重合することができる。 The active energy ray crosslinkable structural site includes, for example, a structure having a radically polymerizable functional group having a carbon-carbon double bond such as a functional group having an unsaturated double bond such as a (meth) acryloyl group or a vinyl group. Can be mentioned.
Since the polymer chain of the (meth) acrylic acid ester (co) polymer has a radically polymerizable functional group, the polymer chains can be directly polymerized even when the cross-linking agent is not contained.
　（メタ）アクリル酸エステル（共）重合体にラジカル重合性官能基を有する構造を導入するには、例えば、共重合成分として、水酸基やカルボキシ基等の官能基を有するモノマーを用いて、（メタ）アクリル酸エステル共重合体を製造した後、この官能基と反応し得る官能基および不飽和二重結合を有する化合物（例えば、２－イソシアナトエチル（メタ）アクリレート等）を、不飽和二重結合の重合性を維持したまま反応させればよい。 In order to introduce a structure having a radically polymerizable functional group into the (meth) acrylic acid ester (co) polymer, for example, a monomer having a functional group such as a hydroxyl group or a carboxy group is used as a copolymerization component (meth). ) After producing the acrylic acid ester copolymer, a compound having a functional group capable of reacting with this functional group and an unsaturated double bond (for example, 2-isocyanatoethyl (meth) acrylate, etc.) is added to the unsaturated double. The reaction may be carried out while maintaining the polymerizable property of the bond.
［光重合開始剤（Ａ）］
　前記光硬化性粘着剤組成物に含まれる光重合開始剤（Ａ）は、可視光線、少なくとも３９０ｎｍ、４０５ｎｍおよび４１０ｎｍの波長を有する光線、例えば３８０～７００ｎｍの波長領域の光線の照射によって、ラジカルを発生させて、（メタ）アクリル酸エステル（共）重合体の反応の起点となる可視光開始剤である。前記光重合開始剤（Ａ）が光硬化性粘着剤組成物に含まれることにより、光硬化性粘着剤組成物は、可視光により硬化することができる。なお、前記光重合開始剤（Ａ）は、可視光線の照射のみによってラジカルを発生させるものであってもよいし、可視光領域以外の波長領域の光線の照射によってもラジカルを発生させるものであってもよい。 [Photopolymerization Initiator (A)]
The photopolymerization initiator (A) contained in the photocurable pressure-sensitive adhesive composition can generate radicals by irradiation with visible light, light having wavelengths of at least 390 nm, 405 nm and 410 nm, for example, light in the wavelength region of 380 to 700 nm. It is a visible light initiator that is generated and serves as a starting point for the reaction of the (meth) acrylic acid ester (co) polymer. By including the photopolymerization initiator (A) in the photocurable pressure-sensitive adhesive composition, the photo-curable pressure-sensitive adhesive composition can be cured by visible light. The photopolymerization initiator (A) may generate radicals only by irradiation with visible light, or may also generate radicals by irradiation with light in a wavelength region other than the visible light region. You may.
　前記光重合開始剤（Ａ）は、波長４０５ｎｍでの吸光係数が１０ｍＬ／（ｇ・ｃｍ）以上であるのが好ましく、より好ましくは１５ｍＬ／（ｇ・ｃｍ）以上、特に好ましくは２５ｍＬ／（ｇ・ｃｍ）以上である。波長４０５ｎｍでの吸光係数が前記数値以上であることによって、可視光線の照射によって硬化（架橋）を充分に進行することができる。
　一方、波長４０５ｎｍでの吸光係数の上限は、１×１０4ｍＬ／（ｇ・ｃｍ）以下が好ましく、１×１０3ｍＬ／（ｇ・ｃｍ）以下がより好ましい。なお、本発明においては、波長４０５ｎｍでの吸光係数が１０ｍＬ／（ｇ・ｃｍ）未満の光重合開始剤と併用してもよい。 The photopolymerization initiator (A) preferably has an extinction coefficient of 10 mL / (g · cm) or more at a wavelength of 405 nm, more preferably 15 mL / (g · cm) or more, and particularly preferably 25 mL / (g).・ Cm) or more. When the absorption coefficient at a wavelength of 405 nm is equal to or higher than the above value, curing (crosslinking) can be sufficiently proceeded by irradiation with visible light.
On the other hand, the upper limit of the absorption coefficient at a wavelength of 405 nm is preferably 1 × 10 4 mL / (g · cm) or less, and more preferably 1 × 10 3 mL / (g · cm) or less. In the present invention, it may be used in combination with a photopolymerization initiator having an extinction coefficient of less than 10 mL / (g · cm) at a wavelength of 405 nm.
　前記光重合開始剤（Ａ）は、ラジカル発生機構によって大きく２つに分類され、光重合開始剤自身の単結合を開裂分解してラジカルを発生させることができる開裂型光重合開始剤と、光励起した開始剤と系中の水素供与体とが励起錯体を形成し、水素供与体の水素を転移させることができる水素引抜型光重合開始剤とに大別される。
　前記開裂型光重合開始剤は、光照射によってラジカルを発生する際に分解して別の化合物となり、一度励起されると反応開始剤としての機能を有さなくなる。このため、架橋反応が終了した後の粘着剤中に活性種として残存することがなく、粘着剤に予期せぬ光劣化等をもたらす可能性がないため好ましい。 The photopolymerization initiator (A) is roughly classified into two types according to the radical generation mechanism, a cleavage-type photopolymerization initiator capable of cleaving and decomposing a single bond of the photopolymerization initiator itself to generate a radical, and a photoexcitation. The initiator and the hydrogen donor in the system form an excitation complex, and the initiator is roughly classified into a hydrogen abstraction type photopolymerization initiator capable of transferring the hydrogen of the hydrogen donor.
The cleavage-type photopolymerization initiator decomposes to another compound when a radical is generated by light irradiation, and once excited, it loses its function as a reaction initiator. Therefore, it is preferable because it does not remain as an active species in the pressure-sensitive adhesive after the cross-linking reaction is completed and there is no possibility of causing unexpected photodegradation of the pressure-sensitive adhesive.
　前記開裂型光重合開始剤としては、例えば、２－メチル－１－［４－（メチルチオ）フェニル］－２－モルフォリノプロパン－１－オン、２－ベンジル－２－（ジメチルアミノ）－４'－モルホリノブチロフェノン、２－ジメチルアミノ－２－（４－メチルベンジル）－１－（４－モルホリ－４－イル－フェニル）－ブタン－１－オン等のα－アミノアセトフェノン系光重合開始剤；ビス（２，４，６－トリメチルベンゾイル）－フェニルホスフィンオキサイド、２，４，６－トリメチルベンゾイル－ジフェニル－ホスフィンオキサイド、（２，４，６－トリメチルベンゾイル）エトキシフェニルホスフィンオキサイド、ビス（２，６－ジメトキシベンゾイル）２，４，４－トリメチルペンチルホスフィンオキサイド等のアシルホスフィンオキサイド系光重合開始剤；２，２－ジメトキシ－１，２－ジフェニルエタン－１－オン等のベンジルケタール系光重合開始剤；１－ヒドロキシシクロヘキシルフェニルケトン、２－ヒドロキシ－２－メチル－１－フェニル－プロパン－１－オン、１－（４－（２－ヒドロキシエトキシ）フェニル）－２－ヒドロキシ－２－メチル－１－プロパン－１－オン、２－ヒロドキシ－１－［４－｛４－（２－ヒドロキシ－２－メチル－プロピオニル）ベンジル｝フェニル］－２－メチル－プロパン－１－オン、オリゴ（２－ヒドロキシ－２－メチル－１－（４－（１－メチルビニル）フェニル）プロパノン）等のα－ヒドロキシアセトフェノン系光重合開始剤；フェニルグリオキシリック酸メチル等のフェニルグリオキシレート系光重合開始剤や、これら開裂型可視光重合開始剤の誘導体等を挙げることができる。 Examples of the cleavage-type photopolymerization initiator include 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one and 2-benzyl-2- (dimethylamino) -4'. -Α-Aminoacetophenone-based photopolymerization initiator such as morpholinobtyrophenone, 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholi-4-yl-phenyl) -butane-1-one; bis (2,4,6-trimethylbenzoyl) -Phenylphosphinoxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide, bis (2,6- Dimethoxybenzoyl) Acylphosphine oxide-based photopolymerization initiator such as 2,4,4-trimethylpentylphosphine oxide; benzylketal-based photopolymerization initiator such as 2,2-dimethoxy-1,2-diphenylethane-1-one; 1-Hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenyl-propane-1-one, 1-(4- (2-hydroxyethoxy) phenyl) -2-hydroxy-2-methyl-1-propane -1-one, 2-hirodoxy-1- [4- {4- (2-hydroxy-2-methyl-propionyl) benzyl} phenyl] -2-methyl-propane-1-one, oligo (2-hydroxy-2) -Α-Hydroxyacetophenone-based photopolymerization initiator such as methyl-1- (4- (1-methylvinyl) phenyl) propanone; phenylglycoxylate-based photopolymerization initiator such as methyl phenylglycylicate, and these. Examples thereof include derivatives of cleavage-type visible photopolymerization initiators.
　前記開裂型光重合開始剤としては、α－アミノフェノン系光重合開始剤が好ましい。α－アミノフェノン系光重合開始剤は、光照射によって分解する際に酸が発生しないため、偏光板の変色を抑制できる傾向がある。
　なお、本発明においては、α－アミノフェノン系光重合開始剤は光吸収ピークの中心波長が可視光領域から外れており硬化不良の不具合が推測されることから、使用を避けたいところであるが、あえて用いたところ、かかる不具合もなく、偏光板の変色を有効に抑制することができたものである。 As the cleavage-type photopolymerization initiator, an α-aminophenone-based photopolymerization initiator is preferable. Since the α-aminophenone-based photopolymerization initiator does not generate an acid when decomposed by light irradiation, it tends to be able to suppress discoloration of the polarizing plate.
In the present invention, it is desired to avoid using the α-aminophenone-based photopolymerization initiator because the center wavelength of the light absorption peak is out of the visible light region and a defect of curing failure is presumed. When it was intentionally used, it was possible to effectively suppress the discoloration of the polarizing plate without such a problem.
　一方、同じ開裂型光開始剤であっても、アシルホスフィンオキサイド系光重合開始剤やフェニルグリオキシレート系光重合開始剤は通常、光吸収ピークの中心波長が可視光吸収ピークにあり硬化不良の懸念が小さい観点から光重合開始剤として用いていたものであるところ、本発明においては、粘着シートに含まれるアシルホスフィンオキサイド系光重合開始剤、フェニルグリオキシレート系光重合開始剤を少なくすることで偏光板の変色を抑制することができたものである。すなわち、前記開裂型光重合開始剤のなかでもアシルホスフィンオキサイド系光重合開始剤やフェニルグリオキシレート系光重合開始剤等は、光照射によってラジカルを発生する際に分解して酸が発生する。この酸が、偏光板と貼り合わせた後の粘着シートに残存すると、触媒として働き、偏光子を構成するポリビニルアルコール系樹脂のポリエン化による変色を引き起こすことがある。そのため、本発明においては、アシルホスフィンオキサイド系光重合開始剤、フェニルグリオキシレート系光重合開始剤を用いないことが好ましいが、本発明の効果に影響のない範囲（光硬化性粘着剤組成物の０．５質量％以下）で用いてもよい。 On the other hand, even with the same cleavage-type photoinitiator, the acylphosphine oxide-based photoinitiator and the phenylglycioxylate-based photoinitiator usually have the center wavelength of the light absorption peak at the visible light absorption peak and are poorly cured. Since it was used as a photopolymerization initiator from the viewpoint of less concern, in the present invention, the amount of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the pressure-sensitive adhesive sheet should be reduced. It was possible to suppress the discoloration of the polarizing plate. That is, among the cleavage-type photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, phenylglycilate-based photopolymerization initiators, and the like are decomposed to generate acids when radicals are generated by light irradiation. If this acid remains on the pressure-sensitive adhesive sheet after being bonded to the polarizing plate, it may act as a catalyst and cause discoloration due to polyene formation of the polyvinyl alcohol-based resin constituting the polarizing element. Therefore, in the present invention, it is preferable not to use an acylphosphine oxide-based photopolymerization initiator or a phenylglycilate-based photopolymerization initiator, but the range does not affect the effect of the present invention (photocurable pressure-sensitive adhesive composition). 0.5% by mass or less) may be used.
　前記水素引抜型光重合開始剤としては、例えば、ビス（２－フェニル－２－オキソ酢酸）オキシビスエチレン、フェニルグリオキシリックアシッドメチルエステル、オキシ－フェニル－アセチックアシッド２－［２－オキソ－２－フェニル－アセトキシ－エトキシ］エチルエステルとオキシ－フェニル－アセチックアシッド２－［２－ヒドロキシ－エトキシ］エチルエステルの混合物、チオキサントン、２－クロロチオキサントン、３－メチルチオキサントン、２，４－ジメチルチオキサントン、アントラキノン、２－メチルアントラキノン、２－エチルアントラキノン、２－ｔｅｒｔ－ブチルアントラキノン、２－アミノアントラキノン、カンファーキノンやその誘導体、ケトクマリンやその誘導体等のケトクマリン系光重合開始剤等が挙げられる。 Examples of the hydrogen abstraction type photopolymerization initiator include bis (2-phenyl-2-oxoacetic acid) oxybisethylene, phenylglycoxyacid methyl ester, and oxy-phenyl-acetylic acid 2- [2-oxo-. A mixture of 2-phenyl-acetoxy-ethoxy] ethyl ester and oxy-phenyl-acetic acid 2- [2-hydroxy-ethoxy] ethyl ester, thioxanthone, 2-chlorothioxanthone, 3-methylthioxanthone, 2,4-dimethylthioxanthone. , 2-Methylanthraquinone, 2-ethylanthraquinone, 2-tert-butylanthraquinone, 2-aminoanthraquinone, phenylquinone and its derivatives, ketocoumarin-based photopolymerization initiators such as ketocoumarin and its derivatives, and the like.
　前記水素引抜型光重合開始剤としては、ケトクマリン系光重合開始剤が好ましい。ケトクマリン系光重合開始剤は、充分な可視光反応性を有し、添加量を調整することで黄変を実用上問題ない水準に調整でき、偏光板の変色を抑制できる傾向がある。
　なお、本発明においては、黄変の不具合が推測されることからケトクマリン系光重合開始剤を用いることは避けたいところであるが、あえて用いたところ、かかる不具合もなく、偏光板の変色を有効に抑制することができたものである。 As the hydrogen abstraction type photopolymerization initiator, a ketocoumarin-based photopolymerization initiator is preferable. The ketocoumarin-based photopolymerization initiator has sufficient visible light reactivity, yellowing can be adjusted to a practically acceptable level by adjusting the addition amount, and there is a tendency that discoloration of the polarizing plate can be suppressed.
In the present invention, it is desired to avoid using a ketocoumarin-based photopolymerization initiator because a yellowing defect is presumed, but when it was intentionally used, there was no such defect and the discoloration of the polarizing plate was effectively effective. It was able to be suppressed.
　なかでも、光重合開始剤（Ａ）としては、α－アミノアセトフェノン系光重合開始剤および、ケトクマリン系光重合開始剤からなる群から選択される少なくとも１種の光重合開始剤を含有することが好ましい。
　なお、光重合開始剤（Ａ）は、前記に挙げた物質に限定するものではない。前記に挙げた光重合開始剤（Ａ）のうちのいずれか１種またはその誘導体を使用してもよいし、２種以上を組み合わせて使用してもよい。
　また、光重合開始剤（Ａ）の他に、紫外線等の他の光線の照射によってのみラジカルを発生させるものを混合してもよい。 Among them, the photopolymerization initiator (A) may contain at least one photopolymerization initiator selected from the group consisting of an α-aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator. preferable.
The photopolymerization initiator (A) is not limited to the substances listed above. Any one of the above-mentioned photopolymerization initiators (A) or a derivative thereof may be used, or two or more thereof may be used in combination.
Further, in addition to the photopolymerization initiator (A), a substance that generates radicals only by irradiation with other light rays such as ultraviolet rays may be mixed.
　光硬化性粘着剤組成物における光重合開始剤（Ａ）の含有量は（メタ）アクリル酸エステル（共）重合体１００質量部に対して、通常０．１～１０質量部であり、好ましくは０．２～５質量部、より好ましくは０．３～３質量部である。
　光重合開始剤（Ａ）の含有量を前記範囲とすることで、可視光線に対する適度な反応感度を得ることができる。 The content of the photopolymerization initiator (A) in the photocurable pressure-sensitive adhesive composition is usually 0.1 to 10 parts by mass, preferably 0.1 to 10 parts by mass, based on 100 parts by mass of the (meth) acrylic acid ester (co) polymer. It is 0.2 to 5 parts by mass, more preferably 0.3 to 3 parts by mass.
By setting the content of the photopolymerization initiator (A) in the above range, an appropriate reaction sensitivity to visible light can be obtained.
　本発明で用いる光硬化性粘着剤組成物は、前記（メタ）アクリル酸エステル（共）重合体、光重合開始剤（Ａ）の他に、架橋剤及び／又はシランカップリング剤を含有することが好ましい。 The photocurable pressure-sensitive adhesive composition used in the present invention contains a cross-linking agent and / or a silane coupling agent in addition to the (meth) acrylic acid ester (co) polymer and the photopolymerization initiator (A). Is preferable.
［架橋剤］
　前記架橋剤としては、例えば、（メタ）アクリロイル基、エポキシ基、イソシアネート基、カルボキシル基、ヒドロキシ基、カルボジイミド基、オキサゾリン基、アジリジン基、ビニル基、アミノ基、イミノ基、アミド基から選ばれる少なくとも１種の架橋性官能基を有する化合物を挙げることができる。これらは、単独でもしくは２種以上を併せて用いてもよい。また、前記架橋剤としては、架橋性官能基が、脱保護可能な保護基で保護されていてもよく、架橋剤が（メタ）アクリル酸エステル（共）重合体と化学結合した態様でもよい。 [Crosslinking agent]
The cross-linking agent is, for example, at least selected from a (meth) acryloyl group, an epoxy group, an isocyanate group, a carboxyl group, a hydroxy group, a carbodiimide group, an oxazoline group, an aziridine group, a vinyl group, an amino group, an imino group and an amide group. A compound having one kind of crosslinkable functional group can be mentioned. These may be used alone or in combination of two or more. Further, as the cross-linking agent, the cross-linking functional group may be protected by a deprotectable protecting group, or the cross-linking agent may be chemically bonded to a (meth) acrylic acid ester (co) polymer.
　なかでも、（メタ）アクリロイル基、ビニル基等の炭素－炭素二重結合を有する光重合性化合物、とりわけ、多官能（メタ）アクリレートが好ましい。ここで、多官能とは２つ以上の（メタ）アクリロイル基を有するものいう。 Among them, a photopolymerizable compound having a carbon-carbon double bond such as a (meth) acryloyl group and a vinyl group, particularly a polyfunctional (meth) acrylate is preferable. Here, polyfunctional means having two or more (meth) acryloyl groups.
　前記多官能（メタ）アクリレートとしては、例えば、１，４－ブタンジオールジ（メタ）アクリレート、グリセリンジ（メタ）アクリレート、ネオペンチルグリコールジ（メタ）アクリレート、グリセリングリシジルエーテルジ（メタ）アクリレート、１，６－ヘキサンジオールジ（メタ）アクリレート、１，９－ノナンジオールジ（メタ）アクリレートヒドロキシビバリン酸ネオペンチルグリコールジ（メタ）アクリレート、ヒドロキシビバリン酸ネオペングリコールのε－カプロラクトン付加物のジ（メタ）アクリレート、トリシクロデカンジメタクリレート、トリシクロデカンジメタノールジ（メタ）アクリレート、ビスフェノールＡポリエトキシジ（メタ）アクリレート、ビスフェノールＡポリプロポキシジ（メタ）アクリレート、ビスフェノールＦポリエトキシジ（メタ）アクリレート、エチレングリコールジ（メタ）アクリレート等の２官能（メタ）アクリレート；トリメチロールプロパントリオキシエチル（メタ）アクリレート、ε-カプロラクトン変性トリス（２－ヒドロキシエチル）イソシアヌレートトリ（メタ）アクリレート、ペンタエリスリトールトリ（メタ）アクリレート、プロポキシ化ペンタエリスリトールトリ（メタ）アクリレート、エトキシ化ペンタエリスリトールトリ（メタ）アクリレート等の３官能（メタ）アクリレート；ペンタエリスリトールテトラ（メタ）アクリレート、プロポキシ化ペンタエリスリトールテトラ（メタ）アクリレート、エトキシ化ペンタエリスリトールテトラ（メタ）アクリレート、ジペンタエリスリトールヘキサ（メタ）アクリレート、ポリエチレングリコールジ（メタ）アクリレート、トリス（アクリロキシエチル）イソシアヌレート、ジペンタエリスリトールヘキサ（メタ）アクリレート、ジペンタエリスリトールペンタ（メタ）アクリレート、トリペンタエリスリトールヘキサ（メタ）アクリレート、トリペンタエリスリトールペンタ（メタ）アクリレート、トリメチロールプロパントリ（メタ）アクリレート、トリメチロールプロパンポリエトキシトリ（メタ）アクリレート、ジトリメチロールプロパンテトラ（メタ）アクリレート等の４官能以上の（メタ）アクリレート等が挙げられる。
　また、上記以外にも多官能（メタ）アクリレートとしては、例えば、ポリエステル（メタ）アクリレート、エポキシ（メタ）アクリレート、ウレタン（メタ）アクリレート、ポリエーテル（メタ）アクリレート等の多官能（メタ）アクリル系オリゴマーが挙げられる。これらは単独でもしくは２種以上を併せて用いてもよい。
　なかでも、３官能以上の多官能（メタ）アクリレートが好ましく、３官能（メタ）アクリレートがより好ましく、プロポキシ化ペンタエリスリトールトリ（メタ）アクリレートが特に好ましい。 Examples of the polyfunctional (meth) acrylate include 1,4-butaneerythritol di (meth) acrylate, glycerindi (meth) acrylate, neopentythritol glycol di (meth) acrylate, and glycering ricidyl ether di (meth) acrylate, 1. , 6-Hentaerythritol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate Neopentylglycolyl hydroxybivariate di (meth) acrylate, ε-caprolactone adduct of neopenterythritol hydroxyvivariate (Meta) acrylate, tricyclodecandymethacrylate, tricyclodecanedimethanol di (meth) acrylate, bisphenol A polyethoxydi (meth) acrylate, bisphenol A polypropoxydi (meth) acrylate, bisphenol F polyethoxydi (meth) acrylate, ethylene glycol Bifunctional (meth) acrylate such as di (meth) acrylate; trimeritol propanthritoltrioxyethyl (meth) acrylate, ε-caprolactone-modified tris (2-hydroxyethyl) isocyanuratethritol (meth) acrylate, pentaerythritol tri (meth). Pentaerythritol tetra (meth) acrylate, propoxidized pentaerythritol tetra (meth) acrylate, ethoxylated Pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (meth) acrylate, polyethylene glycol di (meth) acrylate, tris (acryloxyethyl) isocyanurate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) Pentaerythritol hexa (meth) acrylate, tripentaerythritol penta (meth) acrylate, trimethritol propanetri (meth) acrylate, trimethylolpropanepolyethoxytri (meth) acrylate, ditrimethylol propanetetra (meth) acrylate, etc. Examples thereof include (meth) acrylates having four or more functions.
In addition to the above, examples of the polyfunctional (meth) acrylate include polyfunctional (meth) acrylics such as polyester (meth) acrylate, epoxy (meth) acrylate, urethane (meth) acrylate, and polyether (meth) acrylate. Examples include oligomers. These may be used alone or in combination of two or more.
Of these, trifunctional or higher polyfunctional (meth) acrylates are preferred, trifunctional (meth) acrylates are more preferred, and propoxylated pentaerythritol tri (meth) acrylates are particularly preferred.
　架橋剤の含有量は、前記（メタ）アクリル酸エステル（共）重合体１００質量部に対して０．５～５０質量部、なかでも１～４０質量部、そのなかでも５～３０質量部の割合であるのが好ましい。かかる含有量を前記範囲とすることで、粘着力と凝集力を高めることができ好ましい。 The content of the cross-linking agent is 0.5 to 50 parts by mass, particularly 1 to 40 parts by mass, and 5 to 30 parts by mass thereof with respect to 100 parts by mass of the (meth) acrylic acid ester (co) polymer. It is preferably a ratio. By setting such a content within the above range, the adhesive force and the cohesive force can be enhanced, which is preferable.
［シランカップリング剤］
　シランカップリング剤は、接着性の向上、なかでもガラス材に対する接着力を高めることができることから好ましい。 [Silane coupling agent]
The silane coupling agent is preferable because it can improve the adhesiveness, and above all, the adhesive force to the glass material.
　シランカップリング剤としては、例えば、ビニル基、アクリロキシ基、メタクリロキシ基のような不飽和基、アミノ基、エポキシ基等とともに、アルコキシ基のような加水分解可能な官能基を有する化合物を挙げることができる。 Examples of the silane coupling agent include a compound having a hydrolyzable functional group such as an alkoxy group as well as an unsaturated group such as a vinyl group, an acryloxy group and a methacryloxy group, an amino group and an epoxy group. can.
　シランカップリング剤としては、例えば、Ｎ－（β－アミノエチル）－γ－アミノプロピルトリメトキシシラン、Ｎ－（β－アミノエチル）－γ－アミノプロピルメチルジメトキシシラン、γ－アミノプロピルトリエトキシシラン、γ－グリシドキシプロピルトリメトキシシラン、γ－メタクリロキシプロピルトリメトキシシラン等が挙げられる。これらは単独でもしくは２種以上を併せて用いてもよい。なかでも、接着性が良好であり、黄変等の変色が少ない等の観点から、γ－グリシドキシプロピルトリメトキシシランが好ましい。 Examples of the silane coupling agent include N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, and γ-aminopropyltriethoxysilane. , Gamma-glycidoxypropyltrimethoxysilane, γ-methacryloxypropyltrimethoxysilane and the like. These may be used alone or in combination of two or more. Of these, γ-glycidoxypropyltrimethoxysilane is preferable from the viewpoints of good adhesiveness and less discoloration such as yellowing.
　前記シランカップリング剤の含有量は、（メタ）アクリル酸エステル（共）重合体１００質量部に対し、通常０．０５～５質量部であり、好ましくは０．１～３質量部である。かかる含有量を前記範囲とすることで、白化の不具合を避け、接着力を高めることができるため好ましい。 The content of the silane coupling agent is usually 0.05 to 5 parts by mass, preferably 0.1 to 3 parts by mass with respect to 100 parts by mass of the (meth) acrylic acid ester (co) polymer. By setting such a content within the above range, it is preferable because the problem of whitening can be avoided and the adhesive strength can be enhanced.
　なお、前記光硬化性粘着剤組成物においては、シランカップリング剤の他に、有機チタネート化合物等のカップリング剤も有効に活用できる。 In the photocurable pressure-sensitive adhesive composition, a coupling agent such as an organic titanate compound can be effectively utilized in addition to the silane coupling agent.
［その他の材料］
　前記光硬化性粘着剤組成物には、その他の成分として、例えば、光安定化剤、紫外線吸収剤、金属不活性化剤、金属腐食防止剤、老化防止剤、帯電防止剤、吸湿剤、発泡剤、消泡剤、無機粒子、粘度調整剤、粘着付与樹脂、光増感剤、蛍光剤等の各種の添加剤、反応触媒（三級アミン系化合物、四級アンモニウム系化合物、ラウリル酸スズ化合物等）等が含まれていてもよい。また、その他、通常の粘着剤組成物に配合される公知の成分が適宜含有されていてもよい。これらのその他の成分は、単独でもしくは２種以上を併せて用いてもよい。 [Other materials]
Other components of the photocurable pressure-sensitive adhesive composition include, for example, a light stabilizer, an ultraviolet absorber, a metal deactivating agent, a metal corrosion inhibitor, an antiaging agent, an antistatic agent, a hygroscopic agent, and foaming. Various additives such as agents, defoaming agents, inorganic particles, viscosity modifiers, tackifier resins, photosensitizers, fluorescent agents, reaction catalysts (tertiary amine compounds, quaternary ammonium compounds, tin laurate compounds) Etc.) etc. may be included. In addition, other known components to be blended in a normal pressure-sensitive adhesive composition may be appropriately contained. These other components may be used alone or in combination of two or more.
（光硬化性粘着剤組成物の調製）
　前記光硬化性粘着剤組成物は、例えば、（メタ）アクリル酸エステル（共）重合体、光重合開始剤（Ａ）好ましくは架橋剤、シランカップリング剤、必要に応じて、その他の材料をそれぞれ所定量混合することにより得られる。
　また、光硬化性粘着剤組成物製造時に熱処理工程を入れてもよく、この場合は、予め、前記光硬化性粘着剤組成物の各成分を混合してから熱処理を行うことが望ましい。
　さらには、前記の混合においては、各種の混合成分を濃縮してマスターバッチ化したものを使用してもよい。 (Preparation of photocurable pressure-sensitive adhesive composition)
The photocurable pressure-sensitive adhesive composition may contain, for example, a (meth) acrylic acid ester (co) polymer, a photopolymerization initiator (A), preferably a cross-linking agent, a silane coupling agent, and if necessary, other materials. Each is obtained by mixing a predetermined amount.
Further, a heat treatment step may be added at the time of producing the photocurable pressure-sensitive adhesive composition. In this case, it is desirable to mix each component of the photo-curable pressure-sensitive adhesive composition in advance and then perform the heat treatment.
Further, in the above-mentioned mixing, a masterbatch obtained by concentrating various mixed components may be used.
　前記混合方法としては、特に制限されず、例えば、万能混練機、プラネタリミキサー、バンバリーミキサー、ニーダー、ゲートミキサー、加圧ニーダー、三本ロール、二本ロール等を用いることができる。光硬化性粘着剤組成物の各成分を混合する際は、必要に応じて溶剤を用いて混合してもよいし、溶剤を含まない無溶剤系として混合してもよい。光硬化性粘着剤組成物を無溶剤系とすることで溶剤が残存せず、耐熱性および耐光性が高まるという利点を備えることができる。 The mixing method is not particularly limited, and for example, a universal kneader, a planetary mixer, a Banbury mixer, a kneader, a gate mixer, a pressurized kneader, a three-roll, a two-roll, or the like can be used. When each component of the photocurable pressure-sensitive adhesive composition is mixed, it may be mixed using a solvent if necessary, or it may be mixed as a solvent-free system containing no solvent. By making the photocurable pressure-sensitive adhesive composition solvent-free, it is possible to have the advantage that no solvent remains and the heat resistance and light resistance are improved.
＜光硬化性粘着シート＞
　光硬化性粘着シートは、前記光硬化性粘着剤組成物から形成されるものであり、例えば、粘着シートが１層のみの単層構成であっても、２層以上の複層構成であってもよいが、２層以上の複層構成が好ましい。また、複層構成の場合には、少なくとも最表層が前記光硬化性粘着剤組成物から形成されていればよいが、全ての層が前記光硬化性粘着剤組成物から形成されていてもよい。 <Photo-curable adhesive sheet>
The photocurable pressure-sensitive adhesive sheet is formed from the photo-curable pressure-sensitive adhesive composition. For example, even if the pressure-sensitive adhesive sheet has a single-layer structure with only one layer, it has a multi-layer structure with two or more layers. Although it may be preferable, a multi-layer structure having two or more layers is preferable. Further, in the case of a multi-layer structure, at least the outermost layer may be formed from the photocurable pressure-sensitive adhesive composition, but all layers may be formed from the photo-curable pressure-sensitive adhesive composition. ..
　前記光硬化性粘着剤組成物から光硬化性粘着シートを形成するには、光硬化性粘着剤組成物を塗工すればよい。前記光硬化性粘着剤組成物を塗工する方法としては、一般的な塗工方法であれば特に限定されず、例えば、ロールコーティング、ダイコーティング、グラビアコーティング、コンマコーティング、スクリーン印刷等の方法が挙げられる。 In order to form a photocurable pressure-sensitive adhesive sheet from the photo-curable pressure-sensitive adhesive composition, the photo-curable pressure-sensitive adhesive composition may be applied. The method for applying the photocurable pressure-sensitive adhesive composition is not particularly limited as long as it is a general coating method, and examples thereof include roll coating, die coating, gravure coating, comma coating, and screen printing. Can be mentioned.
　前記光硬化性粘着シートの厚み（β）は、５０～５００μｍであることが実用性から好ましく、なかでも７０～４００μｍ、特には１００～３００μｍであることがさらに好ましい。 The thickness (β) of the photocurable pressure-sensitive adhesive sheet is preferably 50 to 500 μm, more preferably 70 to 400 μm, and particularly preferably 100 to 300 μm.
　このようにして形成される光硬化性粘着シートは、光を照射することにより硬化する光硬化性を備えるものである。この際、光硬化性粘着シートは、光硬化する余地が残された状態に硬化（「仮硬化」とも称する）されたものであってもよいし、未だ硬化されておらず、かつ、光硬化性を有する未硬化（「未硬化」と称する）のものであってもよい。
　形成される光硬化性粘着シートが、仮硬化されたもの、または未硬化のものであれば、当該光硬化性粘着シートを被着体へ貼合した後、光硬化性粘着シートを光硬化（「本硬化」とも称する）することができ、その結果、凝集力を高めて接着性を高めることができる。 The photocurable pressure-sensitive adhesive sheet thus formed has photocurability that is cured by irradiating with light. At this time, the photocurable pressure-sensitive adhesive sheet may be one that has been cured (also referred to as "temporary curing") in a state where there is room for photo-curing, or has not yet been cured and is photo-cured. It may be uncured (referred to as "uncured") having a property.
If the photocurable pressure-sensitive adhesive sheet to be formed is a temporary-cured one or an uncured one, the photo-curable pressure-sensitive adhesive sheet is attached to an adherend and then the photo-curable pressure-sensitive adhesive sheet is photo-cured (). It can also be referred to as "main curing"), and as a result, the cohesive force can be increased and the adhesiveness can be enhanced.
　前記仮硬化させる場合は、光を照射し、本粘着シートのゲル分率を６０％以下とすればよい。ただし、必ずしも、光を照射して光硬化性粘着シートを仮硬化させなくてもよく、例えば、熱または養生により本粘着シートを仮硬化させてもよい。 In the case of the temporary curing, the gel content of the pressure-sensitive adhesive sheet may be set to 60% or less by irradiating with light. However, it is not always necessary to temporarily cure the photocurable pressure-sensitive adhesive sheet by irradiating it with light, and for example, the present pressure-sensitive adhesive sheet may be temporarily cured by heat or curing.
　また、前記光硬化性粘着シートは、被着体に貼合する前の未使用の状態では、離型シートと積層した離型シート付き粘着シートとしておき、使用する際に離型シートを剥がして用いてもよい。前記離型シートは、通常、光硬化性粘着シートの両面に積層される。前記離型シート付き粘着シートは、例えば、前記光硬化性粘着剤組成物を、離型シート上に塗工し、粘着剤層を形成した後、別の離型シートを積層することで製造することができる。 Further, the photocurable adhesive sheet is left as an adhesive sheet with a release sheet laminated with a release sheet in an unused state before being attached to an adherend, and the release sheet is peeled off when used. You may use it. The release sheet is usually laminated on both sides of a photocurable pressure-sensitive adhesive sheet. The pressure-sensitive adhesive sheet with a release sheet is produced, for example, by applying the photocurable pressure-sensitive adhesive composition on the release sheet to form a pressure-sensitive adhesive layer, and then laminating another release sheet. be able to.
　前記離型シートとしては、公知の離型シートを適宜用いることができ、例えば、ポリエステル系樹脂、ポリオレフィン系樹脂、ポリカーボネート系樹脂、ポリスチレン系樹脂、アクリル系樹脂、トリアセチルセルロース系樹脂、フッ素系樹脂等からなるシートに、シリコーン樹脂を塗布して離型処理したものや、離型紙等を適宜選択して用いることができる。これらは単独でもしくは２種以上が積層されていてもよい。 As the release sheet, a known release sheet can be appropriately used, and for example, a polyester resin, a polyolefin resin, a polycarbonate resin, a polystyrene resin, an acrylic resin, a triacetyl cellulose resin, and a fluorine resin can be used. A sheet made of the above, which is coated with a silicone resin and subjected to a mold release treatment, a mold release paper, or the like can be appropriately selected and used. These may be used alone or in combination of two or more.
　前記離型シートは、波長４１０ｎｍ以下での光線透過率が４０％以下であるものが好ましく、より好ましくは３０％以下であり、特に好ましくは２０％である。離型シートの波長４１０ｎｍ以下での光線透過率が前記数値以下であると、本粘着シートの保管時等に可視光によって光重合が進むのを効果的に防ぐことができる。 The release sheet preferably has a light transmittance of 40% or less at a wavelength of 410 nm or less, more preferably 30% or less, and particularly preferably 20%. When the light transmittance of the release sheet at a wavelength of 410 nm or less is not more than the above-mentioned numerical value, it is possible to effectively prevent photopolymerization by visible light during storage of the adhesive sheet or the like.
　ここで、波長４１０ｎｍ以下での光線透過率が４０％以下である離型シート、すなわち可視光および紫外光の透過を一部遮断する作用を有するシートとしては、例えば、下記の（１）～（７）が挙げられる。
（１）ポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなるキャストフィルムや延伸フィルムの一方の面に、再剥離性をもつ微粘着樹脂を塗布し、他方の面に紫外線吸収剤を含む塗料を塗布してなる紫外線吸収層を備えた積層シート。
（２）ポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなるキャストフィルムや延伸フィルムの一方の面に、紫外線吸収剤を配合した再剥離性をもつ微粘着樹脂を塗布した積層シート。
（３）紫外線吸収剤を配合したポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなるキャストフィルムや延伸フィルムに、再剥離性をもつ微粘着樹脂を塗布した積層シート。
（４）紫外線吸収剤を配合したポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなる層の片面もしくは両面に、紫外線吸収剤を含まない樹脂からなる層を成形してなる多層のキャストフィルムや延伸フィルムの一方の面に、再剥離性をもつ微粘着樹脂を塗布した積層シート。
（５）ポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなるキャストフィルムや延伸フィルムの一方の面に紫外線吸収剤を含む塗料を塗布して紫外線吸収層を設け、さらにその紫外線吸収層の上に再剥離性をもつ微粘着樹脂を塗布した積層シート。
（６）ポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなるキャストフィルムや延伸フィルムの一方の面に紫外線吸収剤を含む塗料を塗布して紫外線吸収層を設け、他方の面に再剥離性をもつ微粘着樹脂を塗布した積層シート。
（７）一方の面に再剥離性をもつ微粘着樹脂を塗布したポリエステル系樹脂、ポリプロピレン系樹脂、ポリエチレン系樹脂等の樹脂からなる樹脂フィルムの他方面と、別途準備した樹脂フィルムとを、紫外線吸収剤を含む接着層ないし粘着層を介して積層した積層シート。 Here, as a release sheet having a light transmittance of 40% or less at a wavelength of 410 nm or less, that is, a sheet having an action of partially blocking the transmission of visible light and ultraviolet light, for example, the following (1) to (1) to ( 7) can be mentioned.
(1) A slightly adhesive resin having removability is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin, and an ultraviolet absorber is applied to the other surface. Laminated sheet with an ultraviolet absorbing layer made by applying the containing paint.
(2) A laminated sheet in which a removable slightly adhesive resin containing an ultraviolet absorber is coated on one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin.
(3) A laminated sheet in which a slightly adhesive resin having removability is applied to a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin containing an ultraviolet absorber.
(4) Multi-layer cast formed by molding a layer made of a resin containing an ultraviolet absorber on one or both sides of a layer made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin containing an ultraviolet absorber. A laminated sheet in which a slightly adhesive resin having removability is applied to one surface of a film or a stretched film.
(5) A paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin to provide an ultraviolet absorbing layer, and the ultraviolet absorbing layer is further provided. A laminated sheet coated with a slightly adhesive resin that has removability.
(6) A paint containing an ultraviolet absorber is applied to one surface of a cast film or a stretched film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin to provide an ultraviolet absorbing layer, and the other surface is re-coated. Laminated sheet coated with a slightly adhesive resin with peelability.
(7) The other side of the resin film made of a resin such as a polyester resin, a polypropylene resin, or a polyethylene resin coated with a slightly adhesive resin having a removability on one surface, and a separately prepared resin film are subjected to ultraviolet rays. A laminated sheet laminated via an adhesive layer or an adhesive layer containing an absorbent.
　前記離型シートの厚みは特に制限されないが、加工性およびハンドリング性の観点からは、２５～５００μｍが好ましく、より好ましくは３８～２５０μｍであり、特に好ましくは５０～２００μｍである。 The thickness of the release sheet is not particularly limited, but from the viewpoint of workability and handleability, it is preferably 25 to 500 μm, more preferably 38 to 250 μm, and particularly preferably 50 to 200 μm.
　前記光硬化性粘着シートの粘着剤層の両面に離型シートが積層される場合、一方の離型シートは、他方の離型シートと同じ積層構成、材料、厚みのものであっても、異なる積層構成、材料、厚みのものであってもよい。また、一方の離型シートと他方の離型シートの剥離力が異なる離型シートを用いてもよい。 When the release sheets are laminated on both sides of the pressure-sensitive adhesive layer of the photocurable pressure-sensitive adhesive sheet, one release sheet is different even if it has the same laminated structure, material, and thickness as the other release sheet. It may have a laminated structure, a material, and a thickness. Further, a release sheet having different peeling forces between one release sheet and the other release sheet may be used.
　また、前記離型シートには、帯電防止層やハードコート層、アンカー層等、必要に応じて他の層を有していてもよい。 Further, the release sheet may have other layers such as an antistatic layer, a hard coat layer, an anchor layer, etc., if necessary.
　形成した粘着剤層に別の離型シートを積層することにより、離型シート付き粘着シートが得られる。 By laminating another release sheet on the formed adhesive layer, an adhesive sheet with a release sheet can be obtained.
　また、光硬化性粘着シートが複層構成である場合は、前記光硬化性粘着剤組成物を、基材シートまたは離型シート上に塗工して、第１番目の粘着シートを形成し、形成した第１番目の粘着シート上に、さらに光硬化性粘着剤組成物を塗工して、第２番目の粘着シートを形成することを繰り返す方法や、別々に第１番目の粘着シートと第２番目の粘着シートを形成した後、その後、それぞれの塗工面同士を貼り合わせる方法、前記光硬化性粘着剤組成物を多層コーティングや共押出成型により第１番目の粘着シートと第２番目の粘着シートを同時に形成する方法により製造することができる。 When the photocurable pressure-sensitive adhesive sheet has a multi-layer structure, the photo-curable pressure-sensitive adhesive composition is applied onto a base material sheet or a release sheet to form a first pressure-sensitive adhesive sheet. A method of repeatedly applying a photocurable pressure-sensitive adhesive composition on the formed first pressure-sensitive adhesive sheet to form a second pressure-sensitive adhesive sheet, or separately the first pressure-sensitive adhesive sheet and the first pressure-sensitive adhesive sheet. A method of forming a second pressure-sensitive adhesive sheet and then bonding the coated surfaces to each other, the photocurable pressure-sensitive adhesive composition is coated with a multi-layer coating or co-extrusion molding to form a first pressure-sensitive adhesive sheet and a second pressure-sensitive adhesive. It can be manufactured by a method of forming sheets at the same time.
　なお、前記光硬化性粘着シートは、前記の様に離型シートを使用せずに、例えば、直接偏光板や被着体（他の構成部材（Ｘ））に光硬化性粘着剤組成物を塗布しシート状に形成してもよく、また、光硬化性粘着剤組成物を直接、押出成形して光硬化性粘着シートとしてもよい。さらには、光硬化性粘着剤組成物を型に注入することによって本粘着シートを成形したり、偏光板と被着体である他の構成部材（Ｘ）の間に光硬化性粘着剤組成物を直接充填することによって、光硬化性粘着シートの態様としてもよい。 In the photocurable pressure-sensitive adhesive sheet, for example, the photo-curable pressure-sensitive adhesive composition is directly applied to a polarizing plate or an adherend (another constituent member (X)) without using a release sheet as described above. It may be applied and formed into a sheet, or the photocurable pressure-sensitive adhesive composition may be directly extruded to form a photo-curable pressure-sensitive adhesive sheet. Further, the present pressure-sensitive adhesive sheet may be formed by injecting the photo-curable pressure-sensitive adhesive composition into a mold, or the photo-curable pressure-sensitive adhesive composition may be formed between the polarizing plate and another constituent member (X) which is an adherend. May be used as an embodiment of a photocurable pressure-sensitive adhesive sheet by directly filling with.
　このようにして得られる光硬化性粘着シートは、光硬化性粘着剤組成物に光重合開始剤（Ａ）としてアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤が含まれる場合、その合計の濃度は０．５質量％以下であり、好ましくは０．２質量％以下、より好ましくは０．１質量％以下、特に好ましくは０．０５質量％以下である。なお、下限は、当然ながら０質量％である。すなわち、前記光硬化性粘着シートは、光照射によって分解され、酸が発生するアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤の含有量を少なくすることにより、酸による偏光板の変色を抑制することができる。
　また、光硬化性粘着シートが２層以上の複層構成である場合は、偏光板に接する層を形成する光硬化性粘着剤組成物に含まれるアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤の濃度が、前記範囲内であればよい。 The photocurable pressure-sensitive adhesive sheet thus obtained contains an acylphosphine oxide-based photopolymerization initiator and a phenylglycilate-based photopolymerization initiator as the photopolymerization initiator (A) in the photocurable pressure-sensitive adhesive composition. In the case, the total concentration is 0.5% by mass or less, preferably 0.2% by mass or less, more preferably 0.1% by mass or less, and particularly preferably 0.05% by mass or less. The lower limit is, of course, 0% by mass. That is, the photocurable pressure-sensitive adhesive sheet is polarized by an acid by reducing the contents of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator, which are decomposed by light irradiation and generate an acid. It is possible to suppress discoloration of the plate.
When the photocurable pressure-sensitive adhesive sheet has a multi-layer structure of two or more layers, the acylphosphine oxide-based photopolymerization initiator and phenylglioxy contained in the photocurable pressure-sensitive adhesive composition forming a layer in contact with the polarizing plate. The concentration of the rate-based photopolymerization initiator may be within the above range.
（光線透過率）
　前記光硬化性粘着シートは、波長３９０ｎｍでの光線透過率が９０％未満であって、かつ、波長４１０ｎｍでの光線透過率が８０％以上である。
　波長４００ｎｍ前後の紫外～可視光領域に吸収をもつ光重合開始剤を配合した光硬化性粘着剤組成物については、光重合開始剤の光吸収が大きく、その吸収に由来する波長３９０ｎｍでの光線透過率が低いほど感光性がよく硬化は進行しやすくなる。
　一方で波長４１０ｎｍでの光線透過率が一定以上に高くないと、光硬化性粘着シートとした際に黄着色し画像表示装置に使用することが困難になる。
　波長３９０ｎｍでの光線透過率が９０％未満であれば、充分な可視光硬化性を担保できるため好ましく、波長４１０ｎｍでの光線透過率が８０％以上であれば、透明性が要求される光学部材の貼合に必要な充分に低いイエローインデックス値（ＹＩ値）を達成できる。 (Light transmittance)
The photocurable pressure-sensitive adhesive sheet has a light transmittance of less than 90% at a wavelength of 390 nm and a light transmittance of 80% or more at a wavelength of 410 nm.
For a photocurable pressure-sensitive adhesive composition containing a photopolymerization initiator having absorption in the ultraviolet to visible light region with a wavelength of around 400 nm, the light absorption of the photopolymerization initiator is large, and light rays at a wavelength of 390 nm derived from the absorption are large. The lower the transmittance, the better the photosensitivity and the easier the curing progresses.
On the other hand, if the light transmittance at a wavelength of 410 nm is not higher than a certain level, the photocurable adhesive sheet will be colored yellow and difficult to use in an image display device.
When the light transmittance at a wavelength of 390 nm is less than 90%, sufficient visible light curability can be ensured, which is preferable. When the light transmittance at a wavelength of 410 nm is 80% or more, an optical member requiring transparency is required. It is possible to achieve a sufficiently low yellow index value (YI value) required for bonding.
　前記光硬化性粘着シートの波長３９０ｎｍでの光線透過率は９０％未満であり、好ましくは８８％以下である。
　また、前記光硬化性粘着シートの波長４１０ｎｍでの光線透過率は８０％以上であり、好ましくは８５％以上、特に好ましくは９０％以上である。
　光硬化性粘着シートの光線透過率を前記のようにするには、可視光に吸収のある光重合開始剤（Ａ）のうち、吸収ピークの裾野が３９０ｎｍまでは充分届いているのに対し、４１０ｎｍでは吸収ピークが小さくなる吸光ピーク特性をもつもの、特にはα－アミノアセトフェノン系光重合開始剤及び、ケトクマリン系光重合開始剤からなる群から選択される少なくとも１種を用いればよい。ただし、かかる方法に限定するものではない。 The light transmittance of the photocurable pressure-sensitive adhesive sheet at a wavelength of 390 nm is less than 90%, preferably 88% or less.
The light transmittance of the photocurable pressure-sensitive adhesive sheet at a wavelength of 410 nm is 80% or more, preferably 85% or more, and particularly preferably 90% or more.
In order to obtain the light transmittance of the photocurable pressure-sensitive adhesive sheet as described above, among the photopolymerization initiators (A) having absorption in visible light, the base of the absorption peak reaches 390 nm, whereas the base of the absorption peak is sufficiently reached. At least one selected from the group consisting of an α-aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator having an absorption peak characteristic in which the absorption peak becomes small at 410 nm may be used. However, the method is not limited to this method.
　そして、前記光硬化性粘着シートは、波長３９０～４１０ｎｍの光照射においても硬化できるものである。 The photocurable pressure-sensitive adhesive sheet can be cured even by light irradiation having a wavelength of 390 to 410 nm.
（イエローインデックス値）
　前記光硬化性粘着シートは、透明性の点から、積算光量が３０００（ｍＪ／ｃｍ2）となるように高圧水銀ランプＵＶ光を照射した後、ＪＩＳ　Ｋ７１０３に基づいて測定されるイエローインデックス値が、２．０以下であることが好ましく、１．９以下であることがより好ましい。 (Yellow index value)
From the viewpoint of transparency, the photocurable adhesive sheet has a yellow index value measured based on JIS K7103 after being irradiated with high-pressure mercury lamp UV light so that the integrated light amount is 3000 (mJ / cm 2 ). , 2.0 or less, more preferably 1.9 or less.
（ゲル分率）
　前記光硬化性粘着シートにおける光照射前のゲル分率Ｇ１は、通常、５０％以下、好ましくは４０％以下、特に好ましくは２０％以下である。なお、下限は０％である。ゲル分率が前記数値以下であれば、光照射によって硬化する余地のある未架橋成分が充分多くあり（仮硬化状態または未硬化状態にあり）、柔軟性が高くなる傾向がある。 (Gel fraction)
The gel fraction G1 of the photocurable pressure-sensitive adhesive sheet before light irradiation is usually 50% or less, preferably 40% or less, and particularly preferably 20% or less. The lower limit is 0%. When the gel fraction is equal to or less than the above value, there are sufficiently many uncrosslinked components that can be cured by light irradiation (in a pre-cured state or an uncured state), and the flexibility tends to be high.
　前記ゲル分率は、以下の方法により求められる。
　前記光硬化性粘着シートの質量（浸漬前質量）を測定し、これをＳＵＳメッシュ（♯２００）で袋状に包み、酢酸エチルに浸漬させ２３℃で２４時間暗所保管する。その後、包みを取り出して、７０℃で４．５時間加熱し付着している酢酸エチルを蒸発させ、残った光硬化性粘着シートの質量（浸漬後質量）を測定し、下記の式からゲル分率を求める。
　ゲル分率（％）＝［（浸漬後質量）／（浸漬前質量）］×１００ The gel fraction is determined by the following method.
The mass (mass before immersion) of the photocurable pressure-sensitive adhesive sheet is measured, wrapped in a bag shape with SUS mesh (# 200), immersed in ethyl acetate, and stored in a dark place at 23 ° C. for 24 hours. Then, the package is taken out and heated at 70 ° C. for 4.5 hours to evaporate the adhered ethyl acetate, and the mass (mass after immersion) of the remaining photocurable adhesive sheet is measured, and the gel content is measured from the following formula. Find the rate.
Gel fraction (%) = [(mass after immersion) / (mass before immersion)] × 100
　前記光照射前のゲル分率Ｇ１を前記範囲に調整するには、（メタ）アクリル酸エステル（共）重合体の重合時、および光硬化性粘着シートの加工時に残存触媒を充分除去する、あるいは重合禁止剤、酸化防止剤を使用する等により、本硬化前に熱、光等による意図しない硬化（架橋）反応が進まないようにすればよい。また、光照射によって仮硬化を施す場合には、仮硬化させるために照射する光の積算光量を充分小さくし、未架橋成分が充分多くなるようにすればよい。ただし、かかる方法に限定するものではない。 In order to adjust the gel fraction G1 before light irradiation to the above range, the residual catalyst is sufficiently removed during the polymerization of the (meth) acrylic acid ester (co) polymer and the processing of the photocurable pressure-sensitive adhesive sheet, or By using a polymerization inhibitor, an antioxidant, or the like, it is sufficient to prevent an unintended curing (crosslinking) reaction due to heat, light, or the like from proceeding before the main curing. Further, when the temporary curing is performed by light irradiation, the integrated light amount of the light to be irradiated for the temporary curing may be sufficiently small so that the uncrosslinked component is sufficiently large. However, the method is not limited to this method.
　また、光硬化性粘着シートに紫外線遮蔽性を有する紫外線遮蔽性部材を介して波長４０５ｎｍでの積算光量が３０００（ｍＪ／ｃｍ2）である光を照射した際、光照射後のゲル分率Ｇ２は、通常、４０～１００％、好ましくは５０～１００％、特に好ましくは６０～１００％である。光硬化性粘着シートの光照射後のゲル分率Ｇ２が前記範囲内であれば、過酷な高温高湿環境下においても発泡、剥がれ等の外観不良が見られない傾向がある。 Further, when the photocurable adhesive sheet is irradiated with light having an integrated light amount of 3000 (mJ / cm 2 ) at a wavelength of 405 nm through an ultraviolet shielding member having an ultraviolet shielding property, the gel fraction G2 after the light irradiation. Is usually 40 to 100%, preferably 50 to 100%, and particularly preferably 60 to 100%. When the gel fraction G2 after light irradiation of the photocurable adhesive sheet is within the above range, there is a tendency that appearance defects such as foaming and peeling are not observed even in a harsh high temperature and high humidity environment.
　また、光照射前のゲル分率Ｇ１と光照射後のゲル分率Ｇ２との差（光照射後のゲル分率Ｇ２－光照射前のゲル分率Ｇ１）が１０％以上であることが好ましく、より好ましくは３０％以上であり、特に好ましくは６０％以上である。光硬化前後の光硬化性粘着シートのゲル分率差が前記数値以上であれば、過酷な高温高湿環境等においても高凝集力となり、耐発泡信頼が高くなる傾向がある。なお、上限は通常１００％である。
　前記光照射前後の光硬化性粘着シートのゲル分率差が前記数値以上とするには、例えば、波長４０５ｎｍに吸収のある光重合開始剤（Ａ）を用いればよい。ただし、かかる方法に限定するものではない。 Further, the difference between the gel fraction G1 before light irradiation and the gel fraction G2 after light irradiation (gel fraction G2-after light irradiation 2-gel fraction G1 before light irradiation) is preferably 10% or more. , More preferably 30% or more, and particularly preferably 60% or more. When the difference in gel fraction of the photocurable pressure-sensitive adhesive sheet before and after photo-curing is equal to or greater than the above value, high cohesive force is obtained even in a harsh high-temperature and high-humidity environment, and foam resistance tends to be high. The upper limit is usually 100%.
In order to make the gel fraction difference of the photocurable pressure-sensitive adhesive sheet before and after light irradiation equal to or more than the above value, for example, a photopolymerization initiator (A) having absorption at a wavelength of 405 nm may be used. However, the method is not limited to this method.
　なお、前記「紫外線遮蔽性を有する」とは、波長３６５ｎｍでの光線透過率が１０％以下、かつ、波長４０５ｎｍでの光線透過率が６０％以上であることをいう。このような紫外線遮蔽性部材としては、例えば、三菱ガス化学社製「ユーピロンシートＭＲ５８、厚み１．０ｍｍ」を用いればよい。 The above-mentioned "having ultraviolet shielding property" means that the light transmittance at a wavelength of 365 nm is 10% or less and the light transmittance at a wavelength of 405 nm is 60% or more. As such an ultraviolet shielding member, for example, "Iupilon sheet MR58, thickness 1.0 mm" manufactured by Mitsubishi Gas Chemical Company, Inc. may be used.
　また、「波長４０５ｎｍでの積算光量」とは、単位面積あたりに受ける照射エネルギーの総量であり、高圧水銀ランプ等により照射された光のうち、紫外線積算光量計「ＵＩＴ－２５０」（ウシオ電機社製）および受光器「ＵＶＤ－Ｃ４０５」（ウシオ電機社製）を用いて測定された光照射エネルギーの総量を指し、受光器の感光特性（４０５ｎｍを感光ピークとして、３２０～４７０ｎｍの波長範囲までに裾野が広がる光感度を有する）に応じた波長領域での積算光量を指す。より具体的には、実施例に記載の方法に準拠して求められる積算光量をいう。 The "integrated light amount at a wavelength of 405 nm" is the total amount of irradiation energy received per unit area, and among the light emitted by a high-pressure mercury lamp or the like, the ultraviolet integrated light meter "UIT-250" (Ushio Denki Co., Ltd.) ) And the total amount of light irradiation energy measured using the photoreceiver "UVD-C405" (manufactured by Ushio Denki Co., Ltd.). It refers to the integrated amount of light in the wavelength range according to (having a light sensitivity with a wide base). More specifically, it refers to the integrated light intensity obtained in accordance with the method described in the examples.
　前記光硬化性粘着シートは、上述したように、偏光板／光硬化性粘着シートの層構成に積層され、その積層構造を有するものが、本積層体となる。 As described above, the photocurable pressure-sensitive adhesive sheet is laminated in the layer structure of the polarizing plate / photo-curable pressure-sensitive adhesive sheet, and the one having the laminated structure is the present laminated body.
（偏光板）
　前記偏光板としては、特に限定はなく、例えば、ポリビニルアルコール系樹脂フィルムにヨウ素化合物分子を吸着配向させたポリビニルアルコール系樹脂層（偏光子）の両面をトリアセチルセルロース系樹脂フィルムやアクリル系樹脂フィルム、ポリエステル系樹脂フィルム、シクロオレフィンポリマー系樹脂フィルム等の保護フィルムで積層したものが挙げられる。なかでも、無延伸のため光学等方性に優れる点から、偏光子の両面をトリアセチルセルロース系樹脂フィルムで積層したものが好ましい。
　また、上記保護フィルムとしては、水分の浸入による偏光子の変色を防止する点から、透湿度が、１～１０００（ｇ／ｍ2／ｄａｙ）であることが好ましく、特には５～８００（ｇ／ｍ2／ｄａｙ）、更には１０～６００（ｇ／ｍ2／ｄａｙ）であることが好ましい。 (Polarizer)
The polarizing plate is not particularly limited. For example, a triacetyl cellulose-based resin film or an acrylic resin film has both sides of a polyvinyl alcohol-based resin layer (polarizer) in which iodine compound molecules are adsorbed and oriented on a polyvinyl alcohol-based resin film. , Polyester-based resin film, cycloolefin polymer-based resin film, and other protective films laminated. Among them, those in which both sides of the stator are laminated with a triacetyl cellulose-based resin film are preferable because they are not stretched and therefore have excellent optical isotropic properties.
Further, the protective film preferably has a moisture permeability of 1 to 1000 (g / m 2 / day), particularly 5 to 800 (g), from the viewpoint of preventing discoloration of the polarizing element due to the infiltration of water. / M 2 / day), more preferably 10 to 600 (g / m 2 / day).
　また、本積層体においては、光硬化性粘着シートと偏光子との距離（α）が、８０μｍ以下であることが重要であり、好ましくは１０～８０μｍ、より好ましくは、１０～５０μｍである。
　なお、前記光硬化性粘着シートと偏光子との距離（α）とは、偏光板の光硬化性粘着シートを貼合する面の偏光子（ポリビニルアルコール系樹脂フィルム層）の表面から、光硬化性粘着シートが偏光板と接する面までの距離である。 Further, in the present laminated body, it is important that the distance (α) between the photocurable pressure-sensitive adhesive sheet and the polarizing element is 80 μm or less, preferably 10 to 80 μm, and more preferably 10 to 50 μm.
The distance (α) between the photocurable pressure-sensitive adhesive sheet and the polarizing element is defined as the photocuring from the surface of the polarizing element (polyvinyl alcohol-based resin film layer) on the surface to which the photocurable pressure-sensitive adhesive sheet of the polarizing plate is bonded. The distance to the surface where the adhesive sheet is in contact with the polarizing plate.
　更に、粘着シートと偏光子との距離（α）と、前記光硬化性粘着シートの厚み（β）との比（α／β）は、偏光板の変色抑制の点から０．１～０．５が好ましく、より好ましく０．１～０．４、特に好ましくは０．１～０．３である。 Further, the ratio (α / β) of the distance (α) between the pressure-sensitive adhesive sheet and the polarizing element and the thickness (β) of the photocurable pressure-sensitive adhesive sheet is 0.1 to 0 from the viewpoint of suppressing discoloration of the polarizing plate. 5 is preferable, more preferably 0.1 to 0.4, and particularly preferably 0.1 to 0.3.
 近年では、軽量化のためディスプレイの薄肉化が指向されており、偏光板についても薄肉化が指向されているところ、偏光板を薄肉化した時に、本積層体においては、光硬化性粘着シートと偏光子との距離（α）が近くなった構成でも、偏光板の変色が抑制できる点で上記範囲とすることが好ましい。 In recent years, thinning of the display has been aimed at in order to reduce the weight, and thinning of the polarizing plate has also been aimed at. Even if the distance (α) from the polarizing element is short, the above range is preferable in that discoloration of the polarizing plate can be suppressed.
　本積層体は、前記光硬化性粘着シートを介して、更に他の構成部材（Ｘ）が積層されることが好ましい。 In this laminated body, it is preferable that another component (X) is further laminated via the photocurable pressure-sensitive adhesive sheet.
（他の構成部材（Ｘ））
　他の構成部材（Ｘ）としては、波長３６５ｎｍでの光線透過率が１０％以下で、かつ、波長４０５ｎｍでの光線透過率が６０％以上であるもの、すなわち、紫外線遮光性を備える部材（紫外線遮光性カバー材）であることが好ましい。
　他の構成部材（Ｘ）が、波長３６５ｎｍでの光線透過率が１０％以下で、かつ、波長４０５ｎｍでの光線透過率が６０％以上であれば、紫外線の透過を充分遮断（カット）し、他の構成部材（Ｘ）自身、および、光硬化性粘着シートを介して位置する偏光板の光劣化を抑制し、かつ、積層体に要求されるレベルにイエローインデックス値（ＹＩ値）を低減することができる。 (Other components (X))
As the other component (X), a member having a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm, that is, a member having an ultraviolet light-shielding property (ultraviolet rays). Light-shielding cover material) is preferable.
If the other component (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light transmittance of 60% or more at a wavelength of 405 nm, it sufficiently blocks (cuts) the transmission of ultraviolet rays. The photodeterioration of the other constituent member (X) itself and the polarizing plate located via the photocurable pressure-sensitive adhesive sheet is suppressed, and the yellow index value (YI value) is reduced to the level required for the laminated body. be able to.
　このような他の構成部材（Ｘ）としては、例えば、樹脂材料を主成分とし、紫外線吸収剤を用いて前記光線透過率を有するように調整されたものを挙げることができる。 Examples of such other constituent members (X) include those having a resin material as a main component and adjusted to have the light transmittance by using an ultraviolet absorber.
　前記樹脂材料としては、例えば、ポリカーボネート系樹脂またはアクリル系樹脂を主成分樹脂として含有する材料を挙げることができる。ここで、「主成分樹脂」とは、他の構成部材（Ｘ）を構成する樹脂のなかで最も含有質量の多い樹脂を意味する。 Examples of the resin material include a material containing a polycarbonate resin or an acrylic resin as a main component resin. Here, the "main component resin" means a resin having the largest mass content among the resins constituting the other constituent member (X).
　光硬化性粘着シートを介して、他の構成部材（Ｘ）を積層する方法は、特に制限されず、偏光板または他の構成部材（Ｘ）のいずれか一方を光硬化性粘着シートと積層させた後に、他方を光硬化性粘着シートと積層させてもよく、また、偏光板および他の構成部材（Ｘ）を同時に、光硬化性粘着シートと積層させてもよい。 The method of laminating the other component (X) via the photocurable pressure-sensitive adhesive sheet is not particularly limited, and either the polarizing plate or the other component (X) is laminated with the photo-curable pressure-sensitive adhesive sheet. After that, the other may be laminated with the photocurable pressure-sensitive adhesive sheet, or the polarizing plate and the other constituent member (X) may be laminated with the photocurable pressure-sensitive adhesive sheet at the same time.
　このようにして得られる積層体は、その後、可視光を照射することにより、光硬化性粘着シートが硬化された積層構造体となる。そして、この積層構造体は、主に車載用の画像表示装置構成部材として用いることができる。 The laminated body thus obtained becomes a laminated structure in which the photocurable adhesive sheet is cured by irradiating with visible light thereafter. The laminated structure can be used mainly as a component of an image display device for an automobile.
　以下、本発明の実施例を比較例とともにさらに詳しく説明する。但し、本発明が、以下に説明する実施例に限定されるものではない。 Hereinafter, examples of the present invention will be described in more detail together with comparative examples. However, the present invention is not limited to the examples described below.
［実施例１］
（光硬化性粘着シートの製造）
　イソボルニルメタクリレート：メタクリル酸メチル＝１：１（質量比）からなる、末端官能基がメタクリロイル基のマクロモノマー（数平均分子量：３０００）を１３．５質量部、ラウリルアクリレートを４３．７質量部、２－エチルヘキシルアクリレートを４０質量部、およびアクリルアミド２．８質量部をランダム共重合してなるアクリル系グラフト共重合体（質量平均分子量：１６万）１ｋｇに対し、光重合開始剤としてα－アミノアセトフェノン系の２－ベンジル－２－（ジメチルアミノ）－４'－モルホリノブチロフェノン（ＩＧＭ社製：Ｏｍｎｉｒａｄ３６９）１５ｇ、架橋剤としてプロポキシ化ペンタエリスリトールトリアクリレート（新中村化学社製、ＮＫエステルＡＴＭ－４ＰＬ）５０ｇ、シランカップリング剤として３－グリシジルオキシプロピルトリメトキシシラン（信越化学社製：ＫＢＭ４０３）１．５ｇを添加し、均一混合して、光硬化性粘着剤組成物を得た。
　次に、前記光硬化性粘着剤組成物を、表面が剥離処理されているポリエチレンテレフタレートフィルム（三菱ケミカル社製、ダイアホイルＭＲＶ、厚み１００μｍ）上に、厚み１５０μｍとなるようシート状に成形した後、表面が剥離処理されているポリエチレンテレフタレートフィルム（三菱ケミカル社製、ダイアホイルＭＲＱ、厚み７５μｍ）を被覆し、離型シート付き光硬化性粘着シートを製造した。 [Example 1]
(Manufacturing of photocurable adhesive sheet)
Isobornyl methacrylate: 13.5 parts by mass of macromonomer (number average molecular weight: 3000) having a terminal functional group of methacryloyl group consisting of methyl methacrylate = 1: 1 (mass ratio), 43.7 parts by mass of lauryl acrylate. , Α-Amino as a photopolymerization initiator with respect to 1 kg of an acrylic graft copolymer (mass average molecular weight: 160,000) obtained by randomly copolymerizing 40 parts by mass of 2-ethylhexyl acrylate and 2.8 parts by mass of acrylamide. Acetphenone-based 2-benzyl-2- (dimethylamino) -4'-morpholinobtyrophenone (IGM: Omnirad369) 15 g, propoxylated pentaerythritol triacrylate as a cross-linking agent (NK ester ATM-4PL, manufactured by Shin-Nakamura Chemical Co., Ltd.) 50 g and 1.5 g of 3-glycidyloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd .: KBM403) as a silane coupling agent were added and uniformly mixed to obtain a photocurable pressure-sensitive adhesive composition.
Next, the photocurable pressure-sensitive adhesive composition is formed into a sheet having a thickness of 150 μm on a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRV, thickness 100 μm) whose surface has been peeled off. , A polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, Diafoil MRQ, thickness 75 μm) whose surface has been peeled off was coated to produce a photocurable adhesive sheet with a release sheet.
（偏光板）
　偏光板として、ヨウ素が吸着配向されたポリビニルアルコール系樹脂フィルム（１２μｍ）の両面に接着層、トリアセチルセルロース系樹脂フィルム、コート層が順に積層されており、前記ポリビニルアルコール系樹脂フィルム層の表面が、粘着シートを貼合する偏光板の最表面から３５μｍの深さ位置にあるものを用いた。 (Polarizer)
As a polarizing plate, an adhesive layer, a triacetyl cellulose-based resin film, and a coat layer are laminated in this order on both sides of a polyvinyl alcohol-based resin film (12 μm) in which iodine is adsorbed and oriented, and the surface of the polyvinyl alcohol-based resin film layer is formed on the surface. , A polarizing plate to which the pressure-sensitive adhesive sheet was attached was used at a depth of 35 μm from the outermost surface.
（他の構成部材（Ｘ））
　他の構成部材（Ｘ）として、紫外線遮蔽性を有するポリカーボネート系樹脂板（厚み１．０ｍｍ、３６５ｎｍでの光線透過率０％、４０５ｎｍでの光線透過率８３％、三菱ガス化学社製、ユーピロンシートＭＲ５８）を用いた。 (Other components (X))
As another component (X), a polycarbonate resin plate having an ultraviolet shielding property (thickness 1.0 mm, light transmittance of 0% at 365 nm, light transmittance of 83% at 405 nm, Mitsubishi Gas Chemical Company, Iupilon sheet) MR58) was used.
（積層体の製造）
　離型シート付き光硬化性粘着シートの一方の面の離型シートを剥がし、前記偏光板の一方の面にロール貼合したのち、光硬化性粘着シートのもう一方の面の離型シートを剥がし、前記他の構成部材（Ｘ）として紫外線遮蔽性を有するポリカーボネート系樹脂板をロール貼合し、偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。
　得られた積層体の光硬化性粘着シートと偏光子との距離（偏光板の光硬化性粘着シートを貼合する面のポリビニルアルコール系樹脂フィルム層の表面から、光硬化性粘着シートが偏光板と接する面までの距離）は、３５μｍであった。また、光硬化性粘着シートと偏光子との距離と、光硬化性粘着シートの厚みとの比は、０．２であった。 (Manufacturing of laminated body)
Peel off the release sheet on one side of the photocurable pressure-sensitive adhesive sheet with a release sheet, roll and bond it to one side of the polarizing plate, and then peel off the release sheet on the other side of the photo-curable pressure-sensitive adhesive sheet. As the other constituent member (X), a polycarbonate resin plate having an ultraviolet shielding property was rolled and bonded to obtain a laminate of a polarizing plate / a photocurable pressure-sensitive adhesive sheet / a polycarbonate resin plate having an ultraviolet shielding property.
Distance between the photocurable pressure-sensitive adhesive sheet of the obtained laminate and the polarizing element (The photo-curable pressure-sensitive adhesive sheet is a polarizing plate from the surface of the polyvinyl alcohol-based resin film layer on the surface to which the photo-curable pressure-sensitive adhesive sheet of the polarizing plate is bonded. The distance to the surface in contact with the light) was 35 μm. The ratio of the distance between the photocurable pressure-sensitive adhesive sheet and the polarizing element to the thickness of the photo-curable pressure-sensitive adhesive sheet was 0.2.
［実施例２］
　光重合開始剤として、α－アミノアセトフェノン系の２－ジメチルアミノ－２－（４－メチルベンジル）－１－（４－モルホリノフェニル）－ブタン－１－オン（ＩＧＭ社製：Ｏｍｎｉｒａｄ３７９）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Example 2]
As a photopolymerization initiator, 15 g of α-aminoacetophenone-based 2-dimethylamino-2- (4-methylbenzyl) -1- (4-morpholinophenyl) -butane-1-one (IGM: Omnirad379) was used. A laminated body of a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained in the same manner as in Example 1.
［実施例３］
　光重合開始剤として、α－アミノアセトフェノン系の２－メチル－１－［４－（メチルチオ）フェニル］－２－モルホリノプロパン－１－オン（ＩＧＭ社製：Ｏｍｎｉｒａｄ９０７）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Example 3]
Examples except that 15 g of α-aminoacetophenone-based 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one (IGM: Omnirad907) was used as the photopolymerization initiator. In the same manner as in No. 1, a laminated body of a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
［実施例４］
　光重合開始剤として、ケトクマリン系のケトクマリン誘導体（ＩＧＭ社製：Ｅｓａｃｕｒｅ３６４４）５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Example 4]
A photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / photo-curable pressure-sensitive adhesive in the same manner as in Example 1 except that 5 g of a ketocoumarin-based ketocoumarin derivative (manufactured by IGM: Esacure3644) was used as the photopolymerization initiator. A laminated body of a sheet / polycarbonate resin plate having an ultraviolet shielding property was obtained.
［実施例５］
　光重合開始剤として，アシルホスフィンオキサイド系のフェニル（２，４，６-トリメチルベンゾイル）ホスフィン酸エチル（ＩＧＭ社製：Ｏｍｎｉｒａｄ ＴＰＯ－Ｌ）３ｇ、架橋剤としてペンタエリスリトールトリアクリレート（新中村化学社製、ＮＫエステルＡＴＭＭ－３Ｌ）５０ｇ、を使用した以外は実施例１と同様にして得た光硬化性粘着剤組成物を、中間層用粘着シート（１）（厚さ：２００μｍ）とした。
　光重合開始剤として、アシルホスフィンオキサイド系のフェニル（２，４，６-トリメチルベンゾイル）ホスフィン酸エチル（ＩＧＭ社製：Ｏｍｎｉｒａｄ ＴＰＯ－Ｌ）３ｇ、架橋剤としてプロポキシ化ペンタエリスリトールトリアクリレート（新中村化学社製、ＮＫエステルＡＴＭ－４ＰＬ）８０ｇ、を使用した以外は実施例１と同様にして得た光硬化性粘着剤組成物を、表裏層用粘着シート（２）（厚さ：２５μｍ）、（‘２’）（厚さ：２５μｍ）とした。
　中間層用粘着シートの両側のＰＥＴフィルムを順次剥離除去すると共に、表層用粘着シート（２）及び（‘２’）の粘着面を両表面に順次貼合し、（２）／（１）／（‘２’）からなる厚さ２５０μｍの離型シート付き光硬化性粘着シートを作製した。
　その後、実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Example 5]
Acylphosphinoxide-based ethyl phosphinate (manufactured by IGM: Omnirad TPO-L) 3 g as a photopolymerization initiator, and pentaerythritol triacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.) as a cross-linking agent. , NK Ester ATMM-3L) 50 g) was used, and the photocurable pressure-sensitive adhesive composition obtained in the same manner as in Example 1 was used as an intermediate layer pressure-sensitive adhesive sheet (1) (thickness: 200 μm).
Acylphosphinoxide-based phenyl (2,4,6-trimethylbenzoyl) ethyl phosphinate (IGM: Omnirad TPO-L) 3 g as a photopolymerization initiator, propoxylated pentaerythritol triacrylate (Shin-Nakamura Kagaku) as a cross-linking agent. The photocurable pressure-sensitive adhesive composition obtained in the same manner as in Example 1 except that 80 g of NK ester ATM-4PL manufactured by the same company was used as a pressure-sensitive adhesive sheet for front and back layers (2) (thickness: 25 μm), (thickness: 25 μm). '2') (thickness: 25 μm).
The PET films on both sides of the adhesive sheet for the intermediate layer are sequentially peeled off and removed, and the adhesive surfaces of the adhesive sheets (2) and ('2') for the surface layer are sequentially bonded to both surfaces, and (2) / (1) /. A 250 μm-thick photocurable pressure-sensitive adhesive sheet with a release sheet made of ('2') was produced.
Then, in the same manner as in Example 1, a laminated body of a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
［比較例１］
　光重合開始剤として、アシルホスフィンオキサイド系のジフェニル（２，４，６－トリメチルベンゾイル）ホスフィンオキシド（ＩＧＭ社製：Ｏｍｎｉｒａｄ　ＴＰＯ）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Comparative Example 1]
Similar to Example 1, with a release sheet, except that 15 g of acylphosphine oxide-based diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (manufactured by IGM: Omnirad TPO) was used as the photopolymerization initiator. A laminated body of a photocurable pressure-sensitive adhesive sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
［比較例２］
　光重合開始剤として、アシルホスフィンオキサイド系のフェニル（２，４，６－トリメチルベンゾイル）ホスフィン酸エチル（ＩＧＭ社製：Ｏｍｎｉｒａｄ　ＴＰＯ－Ｌ）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Comparative Example 2]
As the photopolymerization initiator, 15 g of an acylphosphine oxide-based phenyl (2,4,6-trimethylbenzoyl) ethyl phosphinate (manufactured by IGM: Omnirad TPO-L) was used, but the separation was carried out in the same manner as in Example 1. A laminated body of a photocurable pressure-sensitive adhesive sheet with a mold sheet and a polarizing plate / a photo-curable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
［比較例３］
　光重合開始剤として、アシルホスフィンオキサイド系の混合物〔２，４，６－トリメチルベンゾイル－ジフェニル－ホスフィンオキサイド（濃度比：約４６％）、オリゴ（２－ヒドロキシ－２－メチル－１－（４－（１－メチルビニル）フェニル）プロパノン）（濃度比：約５０％）、２，４，６－トリメチルベンゾフェノン（濃度比：約３．２％）、４－メチルベンゾフェノン（濃度比：約０．８％）〕（ＩＧＭ社製：Ｅｓａｃｕｒｅ　ＫＴＯ４６）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Comparative Example 3]
As a photopolymerization initiator, a mixture of acylphosphine oxides [2,4,6-trimethylbenzoyl-diphenyl-phosphinoxide (concentration ratio: about 46%), oligo (2-hydroxy-2-methyl-1- (4-) (1-Methylvinyl) phenyl) propanone) (concentration ratio: about 50%), 2,4,6-trimethylbenzophenone (concentration ratio: about 3.2%), 4-methylbenzophenone (concentration ratio: about 0.8) %)] (IGM: Esacure KTO46) Same as in Example 1 except that it has a photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate / photo-curable pressure-sensitive adhesive sheet / ultraviolet shielding property. A laminate of polycarbonate-based resin plates was obtained.
［比較例４］
　光重合開始剤として、フェニルグリオキシレート系のベンゾイル蟻酸メチル（ＩＧＭ社製：Ｏｍｎｉｒａｄ　ＭＢＦ）１５ｇを使用した以外は実施例１と同様にして、離型シート付き光硬化性粘着シート、および偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Comparative Example 4]
A photocurable pressure-sensitive adhesive sheet with a release sheet and a polarizing plate were obtained in the same manner as in Example 1 except that 15 g of phenylglycilate-based methyl benzoyllate (manufactured by IGM: Omnirad MBF) was used as the photopolymerization initiator. / A laminated body of a photocurable adhesive sheet / a polycarbonate resin plate having an ultraviolet shielding property was obtained.
［参考例］
　偏光板として、ポリビニルアルコール系樹脂フィルム層の表面が、粘着シートを貼合する偏光板の最表面から９０μｍの深さ位置にあるものを用いた以外は比較例１と同様にして、偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体を得た。 [Reference example]
As the polarizing plate, the polarizing plate / is the same as in Comparative Example 1 except that the surface of the polyvinyl alcohol-based resin film layer is located at a depth of 90 μm from the outermost surface of the polarizing plate to which the pressure-sensitive adhesive sheet is attached. A laminate of a photocurable pressure-sensitive adhesive sheet / a polycarbonate-based resin plate having an ultraviolet shielding property was obtained.
　得られた実施例１～５、比較例１～４、参考例の離型シート付き光硬化性粘着シートおよび積層体を用いて、下記の評価を行った。結果を後記の表１に示す。 The following evaluations were performed using the obtained Photocurable Adhesive Sheets with Release Sheets and Laminates of Examples 1 to 5, Comparative Examples 1 to 4, and Reference Examples. The results are shown in Table 1 below.
（１）光線透過率
　離型シート付き光硬化性粘着シートから、離型シートを剥がし、分光光度計（島津製作所社製　ＵＶ２０００）を用いて、光硬化性粘着シートの波長３００～８００ｎｍの分光透過率（％Ｔ）を測定した。 (1) Light transmittance The release sheet is peeled off from the photocurable adhesive sheet with a release sheet, and a spectrophotometer (UV2000 manufactured by Shimadzu Corporation) is used to spectrally transmit the photocurable adhesive sheet at a wavelength of 300 to 800 nm. The rate (% T) was measured.
（２）イエローインデックス値（ＹＩ値）
　離型シート付き光硬化性粘着シートから、離型シートを剥がし、積算光量が３０００（ｍＪ／ｃｍ2）となるよう高圧水銀ランプＵＶ光を照射した後、分光測色計（スガ試験機社製）「ＳＣ－Ｔ」を用いて、ＪＩＳ　Ｋ７１０３に基づきイエローインデックス値（ＹＩ値）を測定した。 (2) Yellow index value (YI value)
The release sheet is peeled off from the photocurable adhesive sheet with a release sheet, and after irradiating with high-pressure mercury lamp UV light so that the integrated light amount becomes 3000 (mJ / cm 2 ), a spectrocolorimeter (manufactured by Suga Test Instruments Co., Ltd.) ) The yellow index value (YI value) was measured based on JIS K7103 using "SC-T".
（３）ゲル分率
　離型シート付き光硬化性粘着シートから、離型シートを剥がし、予め質量（Ｍ）を測定したＳＵＳメッシュ（♯２００）で袋状に包み、袋の口を折って閉じて、この包みの質量（Ｍ1）を測定した後、１００ｍＬの酢酸エチルに浸漬させ２３℃、２４時間暗所保管した後、包みを取り出して７０℃で４．５時間加熱し付着している酢酸エチルを蒸発させ、乾燥した包みの質量（Ｍ2）を測定し、求めた質量を下記式に代入して光照射前のゲル分率Ｇ１を求めた。
　ゲル分率Ｇ１（％）＝［（Ｍ2－Ｍ）／（Ｍ1－Ｍ）］×１００ (3) Gel fraction The release sheet is peeled off from the photocurable adhesive sheet with the release sheet, wrapped in a bag shape with a SUS mesh (# 200) whose mass (M) has been measured in advance, and the mouth of the bag is folded and closed. After measuring the mass (M 1 ) of this package, it was immersed in 100 mL of ethyl acetate and stored in the dark at 23 ° C for 24 hours, then the package was taken out and heated at 70 ° C for 4.5 hours to adhere. Ethyl acetate was evaporated, the mass of the dried package (M 2 ) was measured, and the obtained mass was substituted into the following formula to obtain the gel fraction G1 before light irradiation.
Gel fraction G1 (%) = [(M 2 -M) / (M 1 -M)] × 100
　また、偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体について、紫外線遮蔽性を有するポリカーボネート系樹脂板側から、高圧水銀ランプを用いて、４０５ｎｍでの積算光量が３０００（ｍＪ／ｃｍ2）となるよう光を照射した後、硬化した光硬化性粘着シート部をスパチュラで削り取り、同様の方法で光照射後のゲル分率Ｇ２を求めた。 Further, with respect to the laminate of the polarizing plate / photocurable adhesive sheet / polycarbonate resin plate having ultraviolet shielding property, the integrated light amount at 405 nm from the polycarbonate resin plate side having ultraviolet shielding property using a high pressure mercury lamp. After irradiating with light so as to be 3000 (mJ / cm 2 ), the cured photocurable pressure-sensitive adhesive sheet portion was scraped off with a spatula, and the gel fraction G2 after light irradiation was determined by the same method.
（４）耐高温高湿信頼性
　偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板積層体に対し、紫外線遮蔽性を有するポリカーボネート系樹脂板側から、高圧水銀ランプを用いて、４０５ｎｍでの積算光量が３０００（ｍＪ／ｃｍ2）となるよう光を照射し、耐高温高湿信頼性評価サンプルを作製した。
　前記評価サンプルを、８５℃、８５％ＲＨ環境下に１０００時間暴露した後、下記評価を実施した。
［外観評価］
　発泡や剥離等外観不良が認められなかったものを「○（ｇｏｏｄ）」、発泡や剥離が認められたものを「×（ｐｏｏｒ）」と判定した。
［偏光板の脱色評価］
　目視観察により、偏光板の脱色が認められないものを「○（ｇｏｏｄ）」、明らかに色が薄くなっていることが認められたものを「×（ｐｏｏｒ）」と判定した。 (4) High-temperature and high-moisture reliability Plater / Photocurable adhesive sheet / Polycarbonate-based resin plate laminate with UV-shielding properties, using a high-pressure mercury lamp from the polycarbonate-based resin plate side with UV-shielding properties , Light was irradiated so that the integrated light amount at 405 nm was 3000 (mJ / cm 2 ), and a high temperature and high humidity reliability evaluation sample was prepared.
The evaluation sample was exposed to an environment of 85 ° C. and 85% RH for 1000 hours, and then the following evaluation was carried out.
[Appearance evaluation]
Those in which no appearance defect such as foaming or peeling was observed were judged as "○ (good)", and those in which foaming or peeling was observed were judged as "x (poor)".
[Evaluation of polarizing plate decolorization]
By visual observation, those in which decolorization of the polarizing plate was not observed were determined to be "○ (good)", and those in which the color was clearly lightened were determined to be "x (poor)".
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１～５の積層体は、偏光板と接する層を形成する光硬化性粘着剤組成物に光重合開始剤としてアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤を用いておらず、紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体側からの光照射により光硬化性粘着シートが充分硬化するものであった。また前記光照射後の積層体は、８５℃、８５％ＲＨ、１０００時間暴露後にも偏光板の脱色も発生せず、また、発泡や剥がれ等の外観不具合がない良好な耐湿熱信頼性が得られた。 In the laminates of Examples 1 to 5, an acylphosphine oxide-based photopolymerization initiator and a phenylglycilate-based photopolymerization initiator are added as photopolymerization initiators to the photocurable pressure-sensitive adhesive composition forming a layer in contact with the polarizing plate. The photocurable pressure-sensitive adhesive sheet was sufficiently cured by light irradiation from the laminated body side of the polycarbonate-based resin plate having an ultraviolet shielding property, which was not used. Further, the laminate after light irradiation does not cause decolorization of the polarizing plate even after exposure at 85 ° C., 85% RH, and 1000 hours, and good moisture resistance and heat reliability without appearance defects such as foaming and peeling can be obtained. Was done.
　比較例１～４の、偏光板／光硬化性粘着シート／紫外線遮蔽性を有するポリカーボネート系樹脂板の積層体は、粘着剤層にアシルホスフィンオキサイド系光重合開始剤又はフェニルグリオキシレート系光重合開始剤を特定量以上含むことから、光照射後の積層体が８５℃、８５％ＲＨ、１０００時間暴露後に発泡や剥がれ等の外観不具合はないものの、偏光板に著しい変色が発生した。 In Comparative Examples 1 to 4, the laminate of the polarizing plate / photocurable pressure-sensitive adhesive sheet / UV-shielding polycarbonate-based resin plate has an acylphosphine oxide-based photopolymerization initiator or a phenylglycilate-based photopolymerization on the pressure-sensitive adhesive layer. Since the initiator was contained in a specific amount or more, the laminate after light irradiation had no appearance defects such as foaming and peeling after exposure at 85 ° C., 85% RH, and 1000 hours, but significant discoloration occurred in the polarizing plate.
　また、ポリビニルアルコール系樹脂フィルム層の表面が、粘着シートを貼合する偏光板の最表面から９０μｍの深さ位置にある参考例では、光硬化性粘着剤組成物にアシルホスフィンオキサイド系光重合開始剤を特定量以上含む比較例１の光硬化性粘着シートを用いても、偏光板に変色が発生せず良好な結果であった。
　このことから、本発明は、特に光硬化性粘着シートと偏光子との距離が近い構成において好適に用いることができることを示す。 Further, in the reference example in which the surface of the polyvinyl alcohol-based resin film layer is located at a depth of 90 μm from the outermost surface of the polarizing plate to which the pressure-sensitive adhesive sheet is bonded, the acylphosphine oxide-based photopolymerization is started on the photocurable pressure-sensitive adhesive composition. Even when the photocurable pressure-sensitive adhesive sheet of Comparative Example 1 containing a specific amount or more of the agent was used, discoloration did not occur in the polarizing plate, and good results were obtained.
From this, it is shown that the present invention can be suitably used particularly in a configuration in which the distance between the photocurable pressure-sensitive adhesive sheet and the polarizing element is short.
　上記実施例においては、本発明における具体的な形態について示したが、上記実施例は単なる例示にすぎず、限定的に解釈されるものではない。当業者に明らかな様々な変形は、本発明の範囲内であることが企図されている。 Although the specific embodiment of the present invention has been shown in the above examples, the above examples are merely examples and are not to be construed in a limited manner. Various variations apparent to those skilled in the art are intended to be within the scope of the present invention.
　本発明の積層体は、可視光により硬化し、高温高湿下においても偏光板の変色、発泡や剥がれ等の外観不良を抑制することができるため、車載用の画像表示装置構成部材に好適に用いることができる。 The laminate of the present invention is cured by visible light and can suppress appearance defects such as discoloration, foaming and peeling of the polarizing plate even under high temperature and high humidity, and is therefore suitable for an in-vehicle image display device component. Can be used.

Claims (14)

  1. ［I］偏光板／光硬化性粘着シートの層構成に積層された積層体であって、
    ［II］偏光板が、偏光子の両面が保護フィルムで積層された層構成を有し、
    ［III］光硬化性粘着シートと偏光子との距離（α）が、８０μｍ以下であり、
    ［IV－１］光硬化性粘着シートが、（メタ）アクリル酸エステル（共）重合体および光重合開始剤（Ａ）を含む光硬化性粘着剤組成物から形成され、かつ、
    ［IV－２］波長３９０ｎｍでの光線透過率が９０％未満、波長４１０ｎｍでの光線透過率が８０％以上であり、
    ［IV－３］前記光重合開始剤（Ａ）として前記光硬化性粘着剤組成物に含まれるアシルホスフィンオキサイド系光重合開始剤及びフェニルグリオキシレート系光重合開始剤の合計の濃度が０．５質量％以下である、
    積層体。     [I] A laminate laminated in the layer structure of the polarizing plate / photocurable pressure-sensitive adhesive sheet.
    [II] The polarizing plate has a layer structure in which both sides of the polarizing element are laminated with a protective film.
    [III] The distance (α) between the photocurable adhesive sheet and the polarizing element is 80 μm or less.
    [IV-1] The photocurable pressure-sensitive adhesive sheet is formed from a photo-curable pressure-sensitive adhesive composition containing a (meth) acrylic acid ester (co) polymer and a photopolymerization initiator (A), and
    [IV-2] The light transmittance at a wavelength of 390 nm is less than 90%, and the light transmittance at a wavelength of 410 nm is 80% or more.
    [IV-3] The total concentration of the acylphosphine oxide-based photopolymerization initiator and the phenylglycilate-based photopolymerization initiator contained in the photocurable pressure-sensitive adhesive composition as the photopolymerization initiator (A) is 0. 5% by mass or less,
    Laminated body.
  2. ［IV－４］前記光硬化性粘着シートが、波長３９０～４１０ｎｍの光照射においても硬化できる光硬化性粘着シートである、請求項１記載の積層体。 [IV-4] The laminate according to claim 1, wherein the photocurable pressure-sensitive adhesive sheet is a photo-curable pressure-sensitive adhesive sheet that can be cured even when irradiated with light having a wavelength of 390 to 410 nm.
  3. 　前記光硬化性粘着シートを介して、他の構成部材（Ｘ）が積層され、前記他の構成部材（Ｘ）が、波長３６５ｎｍでの光線透過率が１０％以下、かつ、波長４０５ｎｍでの光線透過率が６０％以上である、請求項１又は２記載の積層体。 Another component (X) is laminated via the photocurable pressure-sensitive adhesive sheet, and the other component (X) has a light transmittance of 10% or less at a wavelength of 365 nm and a light ray at a wavelength of 405 nm. The laminate according to claim 1 or 2, wherein the transmittance is 60% or more.
  4. 　前記他の構成部材（Ｘ）が、紫外線遮光性カバー材である請求項３記載の積層体。 The laminate according to claim 3, wherein the other component (X) is an ultraviolet light-shielding cover material.
  5. 　前記偏光板における保護フィルムが、トリアセチルセルロース系樹脂フィルムである、請求項１～４のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 4, wherein the protective film in the polarizing plate is a triacetyl cellulose-based resin film.
  6.  前記光硬化性粘着シートと偏光子との距離（α）と、前記光硬化性粘着シートの厚み（β）との比（α／β）が０．１～０．５である、請求項１～５のいずれか一項に記載の積層体。 Claim 1 in which the ratio (α / β) of the distance (α) between the photocurable pressure-sensitive adhesive sheet and the polarizing element to the thickness (β) of the photocurable pressure-sensitive adhesive sheet is 0.1 to 0.5. The laminate according to any one of 5 to 5.
  7. 　前記光硬化性粘着シートの厚み（β）が５０～５００μｍである、請求項１～６のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 6, wherein the photocurable pressure-sensitive adhesive sheet has a thickness (β) of 50 to 500 μm.
  8. 　前記光重合開始剤（Ａ）が、α－アミノアセトフェノン系光重合開始剤および、ケトクマリン系光重合開始剤からなる群から選択される少なくとも１種の光重合開始剤を含有する、請求項１～７のいずれか一項に記載の積層体。 Claim 1 to claim 1, wherein the photopolymerization initiator (A) contains at least one photopolymerization initiator selected from the group consisting of an α-aminoacetophenone-based photopolymerization initiator and a ketocoumarin-based photopolymerization initiator. The laminate according to any one of 7.
  9. 　前記光硬化性粘着シートのイエローインデックス値（ＹＩ値）が、２．０以下である、請求項１～８のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 8, wherein the yellow index value (YI value) of the photocurable adhesive sheet is 2.0 or less.
  10. 　前記光硬化性粘着剤組成物が、３官能以上の多官能（メタ）アクリレート及び／又はシランカップリング剤を含有する、請求項１～９のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 9, wherein the photocurable pressure-sensitive adhesive composition contains a trifunctional or higher polyfunctional (meth) acrylate and / or a silane coupling agent.
  11. 　前記（メタ）アクリル酸エステル（共）重合体が、枝成分としてマクロモノマーを備えたグラフト共重合体である、請求項１～１０のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 10, wherein the (meth) acrylic acid ester (co) polymer is a graft copolymer having a macromonomer as a branch component.
  12. 　前記光硬化性粘着シートにおいて、該粘着シートに紫外線遮蔽性を有する紫外線遮蔽性部材を介して波長４０５ｎｍでの積算光量が３０００（ｍＪ／ｃｍ2）である光を照射したときに、光照射前のゲル分率Ｇ１と光照射後のゲル分率Ｇ２との差（光照射後のゲル分率Ｇ２－光照射前のゲル分率Ｇ１）が１０％以上である、請求項１～１１のいずれか一項に記載の積層体。 In the photocurable pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive sheet is irradiated with light having an integrated light amount of 3000 (mJ / cm 2 ) at a wavelength of 405 nm through an ultraviolet-shielding member having an ultraviolet-shielding property, before light irradiation. The difference between the gel fraction G1 after light irradiation and the gel fraction G2 after light irradiation (gel fraction G2-after light irradiation, gel fraction G1 before light irradiation) is 10% or more, any of claims 1 to 11. The laminate according to item 1.
  13. 　前記光硬化性粘着シートが、２層以上の複層構成である、請求項１～１２のいずれか一項に記載の積層体。 The laminate according to any one of claims 1 to 12, wherein the photocurable adhesive sheet has a multi-layer structure of two or more layers.
  14. 　請求項１～１３のいずれか一項に記載の積層体が、可視光により硬化された積層構造体。 The laminated structure according to any one of claims 1 to 13 is a laminated structure cured by visible light.
PCT/JP2021/041559 2020-12-10 2021-11-11 Laminate and laminated structure WO2022124000A1 (en)

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JP2017171703A (en) * 2016-03-18 2017-09-28 日本カーバイド工業株式会社 Adhesive composition and polarizing plate with adhesive layer
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